NetBeans IDE Dev (Build 200701101900)
1.6.0-rc; Java HotSpot(TM) Client VM 1.6.0-rc-b104
Windows XP version 5.1 running on x86

Steps to reproduce:
1. configure tomcat server for dynamic attach through attach wizard -
autointegration
2. start the server
3. attach to the server using e.g. monitoring

Profiler throws an error dialog without message. Log of tomcat server contains:

Profiler Agent: JNI On Load Initializing...
Profiler Agent: JNI OnLoad Initialized succesfully
Profiler Agent: Waiting for connection on port 5140 (Protocol version: 4)

Profiler seems to be at:

org.netbeans.modules.profiler.NetBeansProfiler.displayError(NetBeansProfiler.java:1115)
org.netbeans.modules.profiler.NetBeansProfiler.attachToApp(NetBeansProfiler.java:851)
org.netbeans.modules.profiler.actions.ProfilingSupport.doAttach(ProfilingSupport.java:448)

After confirmation of the error an exception was thrown to ide log:

java.lang.NullPointerException
        at
org.netbeans.modules.profiler.NetBeansProfiler.performInstrumentation(NetBeansProfiler.java:1749)
        at
org.netbeans.modules.profiler.NetBeansProfiler.attachToApp(NetBeansProfiler.java:847)
        at
org.netbeans.modules.profiler.actions.ProfilingSupport.doAttach(ProfilingSupport.java:448)
        at
org.netbeans.modules.profiler.actions.AttachAction.actionPerformed(AttachAction.java:56)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)