...no, this was adding ever deeper debug logging and running the application over and over again to generate output. Once the problem was isolated then I had to sort out what the math was supposed to do and why it wasn't doing it in this case. The floating point error was even in the last decimal place.
If you are really curious, you can drill in on the diff here:
http://code.google.com/p/jmonkeyengine/source/detail?r=10785The comment is 100x longer than the fix.