Gotta love companies that "get it".  Late last night I was hacking away on some Android stuff using IntelliJ 9.0.2 (on Ubuntu 10.04). For reasons unknown to me, none of my breakpoints seemed to be working.  In fact, IntelliJ just didn't seem to be working.  I narrowed it down to the breakpoints I was setting - it seemed that every time the breakpoints were being hit.  I managed to narrow it down to this error:
[ 166030]  ERROR - lij.debugger.impl.InvokeThread - null java.lang.UnsupportedOperationException at com.sun.tools.jdi.ReferenceTypeImpl.sourceDebugExtension(ReferenceTypeImpl.java:774) at org.jetbrains.plugins.ruby.jruby.debug.JRubyPositionManager.getPath(JRubyPositionManager.java:141) at org.jetbrains.plugins.ruby.jruby.debug.JRubyPositionManager.getPsiFileByLocation(JRubyPositionManager.java:156) at org.jetbrains.plugins.ruby.jruby.debug.JRubyPositionManager.getSourcePosition(JRubyPositionManager.java:51) at com.intellij.debugger.engine.CompoundPositionManager.getSourcePosition(CompoundPositionManager.java:51) at com.intellij.debugger.engine.ContextUtil.getSourcePosition(ContextUtil.java:63) at com.intellij.debugger.impl.DebuggerSession$MyDebugProcessListener$2.compute(DebuggerSession.java:462) at com.intellij.debugger.impl.DebuggerSession$MyDebugProcessListener$2.compute(DebuggerSession.java:460) at com.intellij.psi.impl.PsiDocumentManagerImpl$3.run(PsiDocumentManagerImpl.java:298) at com.intellij.psi.impl.PsiDocumentManagerImpl$4.run(PsiDocumentManagerImpl.java:321) at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:695) at com.intellij.psi.impl.PsiDocumentManagerImpl.commitAndRunReadAction(PsiDocumentManagerImpl.java:317) at com.intellij.psi.impl.PsiDocumentManagerImpl.commitAndRunReadAction(PsiDocumentManagerImpl.java:296) at com.intellij.debugger.impl.DebuggerSession$MyDebugProcessListener.paused(DebuggerSession.java:460) at com.intellij.debugger.engine.DebugProcessAdapterImpl.paused(DebugProcessAdapterImpl.java:28) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at com.intellij.util.EventDispatcher.dispatch(EventDispatcher.java:87) at com.intellij.util.EventDispatcher.access$100(EventDispatcher.java:33) at com.intellij.util.EventDispatcher$1.invoke(EventDispatcher.java:64) at $Proxy84.paused(Unknown Source) at com.intellij.debugger.engine.SuspendManagerImpl.notifyPaused(SuspendManagerImpl.java:306) at com.intellij.debugger.engine.SuspendManagerImpl.b(SuspendManagerImpl.java:299) at com.intellij.debugger.engine.SuspendManagerImpl.voteSuspend(SuspendManagerImpl.java:318) at com.intellij.debugger.engine.DebugProcessEvents$1.contextAction(DebugProcessEvents.java:412) at com.intellij.debugger.engine.events.SuspendContextCommandImpl.action(SuspendContextCommandImpl.java:62) at com.intellij.debugger.engine.events.DebuggerCommandImpl.run(DebuggerCommandImpl.java:44) at com.intellij.debugger.engine.DebuggerManagerThreadImpl.processEvent(DebuggerManagerThreadImpl.java:148) at com.intellij.debugger.engine.DebuggerManagerThreadImpl.processEvent(DebuggerManagerThreadImpl.java:36) at com.intellij.debugger.impl.InvokeThread.run(InvokeThread.java:135) at com.intellij.debugger.impl.InvokeThread$WorkerThreadRequest.run(InvokeThread.java:52) at com.intellij.openapi.application.impl.ApplicationImpl$5.run(ApplicationImpl.java:329) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) at java.util.concurrent.FutureTask.run(FutureTask.java:166) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:636) at com.intellij.openapi.application.impl.ApplicationImpl$1$1.run(ApplicationImpl.java:125) [ 166036]  ERROR - lij.debugger.impl.InvokeThread - IntelliJ IDEA 9.0.2  Build #IU-95.66 [ 166036]  ERROR - lij.debugger.impl.InvokeThread - JDK: 1.6.0_18 [ 166036]  ERROR - lij.debugger.impl.InvokeThread - VM: OpenJDK Server VM [ 166036]  ERROR - lij.debugger.impl.InvokeThread - Vendor: Sun Microsystems Inc. [ 166036]  ERROR - lij.debugger.impl.InvokeThread - OS: Linux [ 166036]  ERROR - lij.debugger.impl.InvokeThread - Last Action: Debug
So, the problem to me seemed to be something wonky with IntelliJ.  I e-mailed Jetbrains, explaining the symptoms and the above stack trace.  This morning, I was pleased to find an e-mail from Serge  at Jetbrains.  He suggests disabling the Ruby plug-in that I have installed. BINGO! Worked like a charm.  Problem goes away, and in less than 12 hours since I asked for help.