I'm using Netbeans beta build 7 under JDK 1.3 for OS/2.

Ok, one way I found to easily reproduce this bug is to:

1) Open Newton.java (attached)
2) Set breakpoint at line 205
3) Press F5 to begin the JPDA debugger
4) The debugger will stop at the correct line
5) Scroll a few lines down to "A = findLU(A);" and press F4 to "RUN TO 
CURSOR"
6) Exception will be thrown:

Tue Mar 20 01:54:43 EST 2001java.lang.NullPointerException: null
Annotation: Exception occurred in Request Processor
org.openide.util.RequestProcessor$Holder(task 
org.netbeans.core.ModuleActions$1@e7adabc [-2625, 1])
        at 
org.openide.util.RequestProcessor$Holder.<init>(RequestProcessor.java:234
)
        at 
org.openide.util.RequestProcessor$Task.createHolder(RequestProcessor.java
:274)
        at 
org.openide.util.RequestProcessor.post(RequestProcessor.java:98)
        at 
org.openide.util.RequestProcessor.post(RequestProcessor.java:71)
        at 
org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:89)
        at 
org.netbeans.core.windows.frames.NbFocusManager.processKeyStroke(NbFocusM
anager.java:231)
        at 
org.netbeans.core.windows.frames.NbFocusManager.processEvent(NbFocusManag
er.java:192)
        at 
org.netbeans.core.windows.frames.NbFocusManager$1.run(NbFocusManager.java
:159)
        at 
java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:160)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:399)
        at 
java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:109)
        at 
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:99)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
 
Tue Mar 20 01:54:43 EST 2001java.lang.NullPointerException: null
java.lang.NullPointerException
        at 
org.netbeans.modules.debugger.jpda.LineBreakpoint.set(LineBreakpoint.java
:107)
        at 
org.netbeans.modules.debugger.multisession.SessionBreakpoint.setBreakpoin
t(SessionBreakpoint.java:111)
        at 
org.netbeans.modules.debugger.support.BreakpointSupport.setEvent(Breakpoi
ntSupport.java:172)
        at 
org.netbeans.modules.debugger.support.BreakpointSupport.setLine(Breakpoin
tSupport.java:286)
        at 
org.netbeans.modules.debugger.support.DebuggerSupport.createBreakpoint(De
buggerSupport.java:225)
        at 
org.openide.actions.GoToCursorAction.performAction(GoToCursorAction.java:
124)
        at 
org.openide.util.actions.NodeAction.performAction(NodeAction.java:92)
        at 
org.openide.util.actions.NodeAction.actionPerformed(NodeAction.java:83)
        at org.netbeans.core.ModuleActions$1.run(ModuleActions.java:76)
        at org.openide.util.Task.run(Task.java:124)
[catch] at 
org.openide.util.RequestProcessor$ProcessorThread.run(RequestProcessor.ja
va:567)