Are you using AVG anti-virus also? Check
http://www.gnutellaforums.com/347634-post6.html
Whichever firewall you decide to use, make sure LW is listed as an exception.
Setting up an exception for LimeWire in your software firewall (click in link)
If you don't like the recent version, you can downgrade; see
http://www.gnutellaforums.com/340213-post427.html recommended downgrade version is LW 4.16