Seems to be some problem with the options passed to the interpreter. Can you please turn on detailed logging (http://
wiki.netbeans.org/FaqRubyNBLogging70), run the project again and attach the log here? The log contains the actual 
command that gets executed (with all the options), so that should give us a clue on what's the problem. Thanks.

FINE [org.netbeans.api.extexecution.ExternalProcessBuilder]: Running: (basedir: /ext3/home/deltakilo/NetBeansProjects/
RailsApplication4) "/usr/bin/ruby1.9.1 -Ku -r/home/deltakilo/netbeans-testing/netbeans-dev-200902160201/ruby2/sync-
stdio.rb script/server webrick --port 3000"
FINE [org.netbeans.api.extexecution.ExternalProcessBuilder]: Environment: {GEM_PATH=/usr/lib/ruby1.9.1/gems/1.9.1, 
SHLVL=1, SSH_AGENT_PID=3661, XFILESEARCHPATH=/usr/dt/app-defaults/%L/Dt, SESSION_MANAGER=local/deltakilo-comp:/tmp/.ICE-
unix/3767, XDG_SESSION_COOKIE=675d53ea6fa257af6acd7f9c4994101c-1235038415.49076-1535989814, XDG_DATA_DIRS=/usr/share:/
usr/share:/usr/local/share, PWD=/home/deltakilo/Документы, XCURSOR_THEME=oxy-white, LOGNAME=deltakilo, 
J2D_PIXMAPS=shared, GPG_AGENT_INFO=/tmp/gpg-YgOyZq/S.gpg-agent:3662:1, QT_PLUGIN_PATH=/home/deltakilo/.kde/lib/kde4/
plugins/:/usr/lib/kde4/plugins/, KDE_SESSION_VERSION=4, _=/usr/lib/jvm/default-java/bin/java, NLSPATH=/usr/dt/lib/nls/
msg/%L/%N.cat, SSH_AUTH_SOCK=/tmp/ssh-JTZJaM3518/agent.3518, GS_LIB=/home/deltakilo/.fonts, DM_CONTROL=/var/run/xdmctl, 
LD_LIBRARY_PATH=/usr/lib/jvm/java-6-openjdk/jre/lib/i386/client:/usr/lib/jvm/java-6-openjdk/jre/lib/i386:/usr/lib/jvm/
java-6-openjdk/jre/../lib/i386, KDE_MULTIHEAD=false, DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-
IhHtc28LPj,guid=18b06575184870577407e1b3499d30d0, SHELL=/bin/bash, GTK_RC_FILES=/etc/gtk/gtkrc:/home/deltakilo/.gtkrc::/
home/deltakilo/.kde/share/config/gtkrc, GTK2_RC_FILES=/etc/gtk-2.0/gtkrc:/home/deltakilo/.gtkrc-2.0:/home/
deltakilo/.gtkrc-2.0-kde4:/home/deltakilo/.kde/share/config/gtkrc-2.0, XDM_MANAGED=method=classic, PATH=/usr/local/
sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games, GEM_HOME=/usr/lib/ruby1.9.1/gems/1.9.1, KDE_SESSION_UID=, 
DESKTOP_SESSION=default, KDE_FULL_SESSION=true, MALLOC_CHECK_=2, DISPLAY=:0.0, USER=deltakilo, 
DESKTOP_STARTUP_ID=deltakilo-comp;1235040941;898618;3775_TIME2601830, HOME=/home/deltakilo, WINDOWPATH=7, 
LANG=ru_RU.UTF-8}
FINE [org.netbeans.modules.ruby.railsprojects.server.RailsServerManager]: Port number in project properties:3000
FINE [org.netbeans.modules.ruby.railsprojects.server.RailsServerManager]: Checking port: 3000. Ports in use: []
FINE [org.netbeans.modules.ruby.railsprojects.server.RailsServerManager]: Connecting to 3000, using http validation: 
false
FINE [org.netbeans.api.extexecution.ExternalProcessBuilder]: Running: (basedir: /ext3/home/deltakilo/NetBeansProjects/
RailsApplication4) "/usr/bin/ruby1.9.1 -Ku -r/home/deltakilo/netbeans-testing/netbeans-dev-200902160201/ruby2/sync-
stdio.rb script/server webrick --port 3000"
FINE [org.netbeans.api.extexecution.ExternalProcessBuilder]: Environment: {GEM_PATH=/usr/lib/ruby1.9.1/gems/1.9.1, 
SHLVL=1, SSH_AGENT_PID=3661, XFILESEARCHPATH=/usr/dt/app-defaults/%L/Dt, SESSION_MANAGER=local/deltakilo-comp:/tmp/.ICE-
unix/3767, XDG_SESSION_COOKIE=675d53ea6fa257af6acd7f9c4994101c-1235038415.49076-1535989814, XDG_DATA_DIRS=/usr/share:/
usr/share:/usr/local/share, PWD=/home/deltakilo/Документы, XCURSOR_THEME=oxy-white, LOGNAME=deltakilo, 
J2D_PIXMAPS=shared, GPG_AGENT_INFO=/tmp/gpg-YgOyZq/S.gpg-agent:3662:1, QT_PLUGIN_PATH=/home/deltakilo/.kde/lib/kde4/
plugins/:/usr/lib/kde4/plugins/, KDE_SESSION_VERSION=4, _=/usr/lib/jvm/default-java/bin/java, NLSPATH=/usr/dt/lib/nls/
msg/%L/%N.cat, SSH_AUTH_SOCK=/tmp/ssh-JTZJaM3518/agent.3518, GS_LIB=/home/deltakilo/.fonts, DM_CONTROL=/var/run/xdmctl, 
LD_LIBRARY_PATH=/usr/lib/jvm/java-6-openjdk/jre/lib/i386/client:/usr/lib/jvm/java-6-openjdk/jre/lib/i386:/usr/lib/jvm/
java-6-openjdk/jre/../lib/i386, KDE_MULTIHEAD=false, DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-
IhHtc28LPj,guid=18b06575184870577407e1b3499d30d0, SHELL=/bin/bash, GTK_RC_FILES=/etc/gtk/gtkrc:/home/deltakilo/.gtkrc::/
home/deltakilo/.kde/share/config/gtkrc, GTK2_RC_FILES=/etc/gtk-2.0/gtkrc:/home/deltakilo/.gtkrc-2.0:/home/
deltakilo/.gtkrc-2.0-kde4:/home/deltakilo/.kde/share/config/gtkrc-2.0, XDM_MANAGED=method=classic, PATH=/usr/local/
sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games, GEM_HOME=/usr/lib/ruby1.9.1/gems/1.9.1, KDE_SESSION_UID=, 
DESKTOP_SESSION=default, KDE_FULL_SESSION=true, MALLOC_CHECK_=2, DISPLAY=:0.0, USER=deltakilo, 
DESKTOP_STARTUP_ID=deltakilo-comp;1235040941;898618;3775_TIME2601830, HOME=/home/deltakilo, WINDOWPATH=7, 
LANG=ru_RU.UTF-8}
FINE [org.netbeans.modules.ruby.railsprojects.server.RailsServerManager]: Server startup failed, server type is: 
org.netbeans.modules.ruby.railsprojects.server.WEBrick@9fed2797
FINE [org.netbeans.modules.ruby.railsprojects.server.RailsServerManager]: Could not start 
org.netbeans.modules.ruby.railsprojects.server.WEBrick@9fed2797 in 10 seconds, current server status is NOT_STARTED
FINE [org.netbeans.modules.ruby.railsprojects.server.RailsServerManager]: Server startup failed, server type is: 
org.netbeans.modules.ruby.railsprojects.server.WEBrick@9fed2797

It is the problem of -Ku option of Ruby1.9 branch

                                                           
deltakilo@deltakilo-comp:~/NetBeansProjects/RailsApplication4$ ruby1.8 -Ku  script/server webrick=> Booting 
WEBrick...                                                                            
=> Rails 2.2.2 application started on http://0.0.0.0:3000                                        
=> Ctrl-C to shutdown server; call with --help for options                                       
[2009-02-19 14:21:03] INFO  WEBrick 1.3.1                                                        
[2009-02-19 14:21:03] INFO  ruby 1.8.7 (2008-08-11) [i486-linux]                                 
[2009-02-19 14:21:03] INFO  WEBrick::HTTPServer#start: pid=7501 port=3000                        
^C[2009-02-19 14:21:05] INFO  going to shutdown ...                                              
[2009-02-19 14:21:05] INFO  WEBrick::HTTPServer#start done.                                      
deltakilo@deltakilo-comp:~/NetBeansProjects/RailsApplication4$ ruby1.9 -Ku  script/server webrick
=> Booting WEBrick...                                                                            
/var/lib/gems/1.9.0/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/utils.rb:117:in 
`<module:TextUtils>': invalid multibyte character 
(ArgumentError)                                                                                    
        from /var/lib/gems/1.9.0/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/utils.rb:110:in 
`<module:TMail>'                                                                                                                        
        from /var/lib/gems/1.9.0/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/utils.rb:53:in 
`<top 
(required)>'                                                                                                                       
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in 
require'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/interface.rb:36:in 
`<top 
(required)>'                                                                                                                   
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in 
require'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/mail.rb:34:in `<top 
(required)>'                                                                                                                        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in 
require'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail.rb:2:in `<top 
(required)>'
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in 
require'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/actionmailer-2.2.2/lib/action_mailer.rb:35:in `<top 
(required)>'                        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in 
require'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/rails-2.2.2/lib/initializer.rb:256:in `block in 
require_frameworks'                     
        from /var/lib/gems/1.9.0/gems/rails-2.2.2/lib/initializer.rb:256:in 
`each'                                            
        from /var/lib/gems/1.9.0/gems/rails-2.2.2/lib/initializer.rb:256:in 
`require_frameworks'                              
        from /var/lib/gems/1.9.0/gems/rails-2.2.2/lib/initializer.rb:133:in 
`process'                                         
        from /var/lib/gems/1.9.0/gems/rails-2.2.2/lib/initializer.rb:112:in 
`run'                                             
        from /ext3/home/deltakilo/NetBeansProjects/RailsApplication4/config/environment.rb:13:in `<top 
(required)>'           
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in 
require'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/rails-2.2.2/lib/commands/servers/webrick.rb:59:in `<top 
(required)>'                    
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block in 
require'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'        
        from /var/lib/gems/1.9.0/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'                 
        from /var/lib/gems/1.9.0/gems/rails-2.2.2/lib/commands/server.rb:49:in `<top 
(required)>'                             
        from script/server:3:in 
`require'                                                                                     
        from script/server:3:in 
`<main>'                                                                                      
deltakilo@deltakilo-comp:~/NetBeansProjects/RailsApplication4$ ruby1.9.1 -Ku  script/server 
webrick                           
=> Booting 
WEBrick...                                                                                                         
/usr/lib/ruby1.9.1/gems/1.9.1/gems/actionpack-2.2.2/lib/action_controller/routing/segments.rb:6: warning: encoding 
option is ignored - 
N                                                                                                                    
/usr/lib/ruby1.9.1/gems/1.9.1/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/utils.rb:117:in 
`<module:TextUtils>': invalid multibyte character 
(ArgumentError)                                                                          
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/
utils.rb:110:in 
`<module:TMail>'                                                                                                              
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/
utils.rb:53:in `<top 
(required)>'                                                                                                             
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'     
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block 
in 
require'                                                                                                                          
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'                                                                                                                          
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'     
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/
interface.rb:36:in `<top 
(required)>'                                                                                                         
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'     
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block 
in 
require'                                                                                                                          
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'                                                                                                                          
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'     
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail/
mail.rb:34:in `<top 
(required)>'                                                                                                              
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'     
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block 
in 
require'                                                                                                                          
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'                                                                                                                          
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/actionmailer-2.2.2/lib/action_mailer/vendor/tmail-1.2.3/tmail.rb:2:in 
`<top (required)>'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block 
in require'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/actionmailer-2.2.2/lib/action_mailer.rb:35:in `<top (required)>'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block 
in require'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/rails-2.2.2/lib/initializer.rb:256:in `block in require_frameworks'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/rails-2.2.2/lib/initializer.rb:256:in `each'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/rails-2.2.2/lib/initializer.rb:256:in `require_frameworks'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/rails-2.2.2/lib/initializer.rb:133:in `process'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/rails-2.2.2/lib/initializer.rb:112:in `run'
        from /ext3/home/deltakilo/NetBeansProjects/RailsApplication4/config/environment.rb:13:in `<top (required)>'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block 
in require'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/rails-2.2.2/lib/commands/servers/webrick.rb:59:in `<top (required)>'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `block 
in require'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in 
`new_constants_in'
        from /home/deltakilo/.gem/ruby/1.9.1/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in 
`require'
        from /usr/lib/ruby1.9.1/gems/1.9.1/gems/rails-2.2.2/lib/commands/server.rb:49:in `<top (required)>'
        from script/server:3:in `require'
        from script/server:3:in `<main>'

But without -Ku

deltakilo@deltakilo-comp:~/NetBeansProjects/RailsApplication4$ ruby1.9.1 script/server webrick
=> Booting WEBrick...
/usr/lib/ruby1.9.1/gems/1.9.1/gems/actionpack-2.2.2/lib/action_controller/routing/segments.rb:6: warning: encoding 
option is ignored - N
=> Rails 2.2.2 application started on http://0.0.0.0:3000
=> Ctrl-C to shutdown server; call with --help for options
[2009-02-19 14:28:30] INFO  WEBrick 1.3.1
[2009-02-19 14:28:30] INFO  ruby 1.9.1 (2009-01-30) [i686-linux]
[2009-02-19 14:28:30] INFO  WEBrick::HTTPServer#start: pid=7552 port=3000
^C[2009-02-19 14:28:34] INFO  going to shutdown ...
[2009-02-19 14:28:34] INFO  WEBrick::HTTPServer#start done.

Thanks. We need to fix this for 7.0, but meanwhile you should be able to workaround this  by setting the ruby.no.kcode 
to true -- you can do this for example by adding -J-Druby.no.kcode=true to netbeans_default_options in the <netbeans 
install dir>/etct/netbeans.conf file. Let us know if that doesn't help.

thank you very much!

thanks deltakilo,

As you say, I modified my configuration file, added the -J-Druby.no.kcode=true to netbeans_default_options in the 
<netbeans install dir>/etct/netbeans.conf file.

But seems that the error also exist!

Regards!

It is worth mentioning that you have to restart netbeans in order for this workaround to work. The problem is still present in 6.8 RC2