I had the same problem as eveyone else here. I did a little research on port forwarding and found the site PortForward.com - Free Help Setting up Your Router or Firewall
It will help you configure your router to allow the Gnutella network
This is the page I went to once I clicked on Gnutella.
PortForward.com - Free Help Setting up Your Router or Firewall
It has a listing of different router names. Just find yours and go through the directions. Hope this fixes yours like it did mine.