Your issue is not a common one & I'm not sure about how to configure such. I presume the ip table is in reference to each computer on the network. In that case, set up an exception for limewire/gnutella & which ever ports you normally connect through. These are the standard Firewall instructions for the most common firewalls: Firewall configuration instructions (click on link)

For port forwarding, each account or computer on the network that's using LW would require a separate port forwarding using a different port(s) for each user. Since port forwarding is based on ip of user on network.

Sorry I missed your previous reply. It's funny I take some time off from the forums & you suggest such. lol