Turn your Windows firewall off. Put Limewire on your McAfee's firewall safe rule to let it pass through.

As for your toshiba, I had a look at the manual online & looks like a basic modem with no NAT protection or barrier. I would tend to recommend ethernet cable connection over USB for reliable bandwidth handling however.

Your gnutella.net file might be out of date. Try a combination of these suggestions: If LW Will Not Connect (click on the blue link)