Did you do a 'safe' boot & repair permissions?
Delete your LW preferences folder (however remove the old Downloads.dat file before trashing the folder.) See if LW starts up at all. If it does, close LW & put the old downloads.dat file back inside the preferences folder. Deleting LW Preferences folder in OSX

If still not working, you could try the LW beta LimeWire 5.2.2 (Beta) - Lime Wire & even try one of the older versions see if it works at all. There is a Pro Beta version found at right side of your Pro download page, likewise for older versions. But to install an older version you'd need to first remove the install limewire.pkg file from the Library -> Receipts folder.