You need to check that your port forwarding is working through your router and your own pc's firewall.
You could probably have a friend outside try to telnet into your ip / port and see what happens. Gnutella should print something when you connect. Or at least he shouldn't get a refusal.

Just connecting to other hosts for network packets is not enough, most other people are firewalled so you won't be able to get many files unless your port forwarding is working.