The usual answer is re-installing Java & this one usually does the trick: http://www.apple.com/downloads/macos...update142.html
If it won't let you install it, then remove the java1.4.2update2.pkg from the receipts folder; Receipts folder sample image.

Also try deleting your LW preferences found here: /Users/your_username/Library/Preferences/LimeWire

Also, if your LW is not installed onto your OSX HDD, then move the LW program folder to the OSX applications folder on the OSX HDD.