I spent some time tracking this down.
The error is harmless.
If you are like me, you may have encountered a usability issue that I filed today:
http://www.netbeans.org/issues/show_bug.cgi?id=109901
To get the profiling to work, I needed to follow the directions buried in the Information dialog...
I needed to run the 'Run Profiler Calibration' item of the 'Advanced Commands' submenu of the Profile menu. [Profile->Advanced Commands->Run Profiler Calibration]
vbk
[Message sent by forum member 'vbkraemer' (vbkraemer)]
http://forums.java.net/jive/thread.jspa?messageID=226835