Gees you guys--between the four of us (and others who can chip in), we should be able to track this down!

How about a clean install (again?) and make sure all the Java pieces are where they are supposed to be? jottagirl found an odd situation where the MRJ pieces were misplaced:
http://www.gnutellaforums.com/showth...8843#post78843

To trash all LimeWire pieces and preferences, use Sherlock to search for both visible and invisible "limew".

I'll boot into 9 and see if I can find the minimum extensions needed to run LW (I still suspect an extension conflict).