There's sample images about where to find your LW prefs folder in posts 3 & 4 here Fixes for Limewire. Exactly where you find it depends upon whether you've deleted them before or not & had earlier versions running.

BTW if you've gone back to an earlier version, then you should definitely delete your LW prefs folder. This is because LW 4.8.1 will attempt to behave like LW 4.12 & have problems. Also going back in versions will mean your incomplete files will not load, but you can reload them via the library window.