Ahm...
Select the Finder and open a new window. Go to the Applications folder and delete LW.
Browse to the <username> directory (the "Home" one) and go into the Library. Enter the Preferences folder and find the folder called Limewire-> to the Trash.
http://www.limewire.com/english/cont...pro_lookup.jsp ->enter your email adress and redld Pro (may I suggest at this point that you dld the latest beta Pro).
Reinstall.
Does it still refuse to Launch?