This used to work sometime before October last year.  Since I can't see any
tables at all, I'm filing this as a P1 now.

I go to Runtime->Databases->Drivers and add my odbc14.jar driver.  After that, I
establish a connection as I usually do:
               jdbc:oracle:thin:@neptune.netforensics.com:1521:nfdb
And NB seems content with everything:  I see a DB connection tree that expands
to have "Tables", "Views", and "Procedures".  If I expand "Views" or
"Procedures", I indeed see the views and stored procedures on my database
server.  But when I select "Tables", I get the error:
               Unable to read the database structure, connection error;
Unsupported feature

Colleagues using DBVisualizer with the same ojdbc14.jar have no problem
accessing the tables in the DB.

I'm running FC5.0 Linux with NB 6.0M7 (but it's been a problem since October
last year!) using JDK1.6.  Before filing this bug, I checked the 'net and found
a reference to the same problem in a Sun Bug DB and the evaluation of the bug
stated that it's a bug in dbExplorer - so I'm filing it here.  Here's the
reference to the Sun Bug entry:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6480113