I personally know little about proxies but you could always try different ones. Feedback has said that you may need to try quite a few before you find one that one works.
See:
A Fix for those whose ISP's block Limewire pages 1 & 2 which has a link to alternative instructions.
Also see:
http://www.gnutellaforums.com/showth...threadid=35775
And
http proxies