I am having the same problem with both Frostwire and Limewire, but since Frostwire is the one I am trying to use now I am posting here. It's been ongoing for a few months now. Whenever I launch either app I get "Starting connection" and "Frostwire has detected a firewall", and that's it. I have it set to use UPnP, and I can see in the router settings that the port forwarding is in fact getting set. I tried changing the default port but it doesn't help. I am running Ubuntu 11.10, and both programs did at one time, as in earlier this year even, connect to the network. I am using Frostwire 4.21.8 with java 1.7.0_21.

I am wondering now if Verizon blocked the gnutella network, or if there would be any way to check and see. Any help would be appreciated, thanks.