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?

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iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

"Raise your can of Beer on high
And seal your fate forever
Our best years have passed us by
The Golden Age Of Leather"
-Blue Öyster Cult-