Try updating your Java to the most recent: Java 1.5 (take the JRE)

Leave LW running for about an hour. If no improvement then do this test: Bug Report instructions & sample image & post back whether it's true/false. Also tell us your modem & router brand name & model numbers. Lot's of people have been using NAT modems/routers for years without realising that their setup was not allowing LW full access.

I presume you applied the SP2 patch. And double-checked your firewall settings? SP2 will change your Firewall settings. To be sure check here: http://www.limewire.com/english/content/firewalls.shtml