Are you running Java 1.5 or 1.4.2? You should be running Java 1.5; see
Setting up Java 1.5
Also, it might be wise to delete your LW preferences folder whilst LW is closed; found here /Users/your_username/Library/Preferences/LimeWire
After installing LW did you do a safe boot & repair permissions? Did you do that after updating your OSX updates last time?