netbeans-trunk-nightly-200909221401-javafx-full.zip 

  Product Version         = NetBeans IDE Dev (Build 200909221401) (#038a2843d59a)
  Operating System        = Windows XP version 5.1 running on x86
  Java; VM; Vendor        = 1.6.0_15; Java HotSpot(TM) Client VM 14.1-b02; Sun Microsystems Inc.


I create a file and set a breakpoint. After that I removed the line, copied the code to the editor:
---------------------------------
var a = 10;
var b = 20.5;
var c = a + b;
---------------------------------

and tried to set a breakpoint. 

The NPE pops up:

java.lang.NullPointerException: Passed null to FileOwnerQuery.getOwner(FileObject)
	at org.netbeans.api.project.FileOwnerQuery.getOwner(FileOwnerQuery.java:94)
	at org.netbeans.modules.javafx.debugger.utils.Utils.getFXPath(Utils.java:89)
	at org.netbeans.modules.javafx.debugger.breakpoints.JavaFXLineBreakpoint.<init>(JavaFXLineBreakpoint.java:56)
	at org.netbeans.modules.javafx.debugger.breakpoints.JavaFXLineBreakpoint.create(JavaFXLineBreakpoint.java:82)
	at org.netbeans.modules.javafx.debugger.actions.JavaFXToggleActionProvider.doAction(JavaFXToggleActionProvider.java:58)
	at org.netbeans.spi.debugger.ActionsProvider$1.run(ActionsProvider.java:112)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:602)
	at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1070)
Caused: org.openide.util.RequestProcessor$FastItem: task failed due to