I don't know if this applies to everyone else, but after upgrading to Tiger I found an external firewire capture device wouldn't work due to QuickTime. The solution is here http://docs.info.apple.com/article.html?artnum=301852
After that I installed QT 7.0.4 & LW had no problems running with it at all. I guess the problem might have been having QT 6 still on the system in my receipts folder. But I never did try QT 7.0.4 before that so I don't know if there would have been a problem for me also. (BTW I've heard a rumour Apple might get rid of their firewire options. At least the FW800.)

frozlee try reinstalling your Java. Use the "Offline" installer from the apple site. I'd also recommend updating to Java 1.5 & forcing LW to use 1.5 if you haven't done this already. See http://docs.info.apple.com/article.html?artnum=301073 for instructions for forcing LW to use Java 1.5 & Java 1.5 can be found here Java 1.5 release 3. I'd also recommend deleting your LW preferences folder whilst LW is CLOSED found here /Users/your_username/Library/Preferences/LimeWire