It's probably a corrupt preference file. IIRC, the preference file will be in your user folder/Library/Preferences/ folder. I can't recall the exact name (I'm on a pee cee right now) but I believe it has Limewire and possibly ".plist" in the name.

Quit Limewire, delete the pref file and then start Limewire again.

Reinstalling won't delete this preference file, and if it's corrupt you'll be right back where you started when you first launch LW.

Hope this helps....