Others with Intel Macs had this problem, and I couldn't help them. However, there is a new beta released, and you could also try Jum's alternate LimeWire that uses a different instal method
LimeWire cvs builds (4.13.3jum487) Perhaps either of those will install and run.
Sounds like you have tried the usual suggestions, except the Safe Boot (restarting and holding down the shift key right after the startup tone).
The other way to get more detailed info on the problem is to turn on Console (in the Applications/Utilites folder).