Whilst LW is closed, delete the LW preferences found here /Users/your_username/Library/Preferences/LimeWire
(BTW by deleting your LW prefs folder you will need to reset all your options next time you start LW.)

It would also probably be worth doing a safe boot & repairing permissions. ie: reboot whilst holding down the SHIFT key until you see a message saying SAFE Booting. Once it's started up, open Disk Utility found in your Utilities folder & repair permissions. Then reboot normally.