Take a look at this post http://www.gnutellaforums.com/genera...-10-5-1-a.html
It's my guess the wireless is causing problems. The belkin having it's own firewall. Belkin's are generally best & more reliable port forwarded.

Also make sure your OSX firewall is either turned off or set permissions for LW to operate through; OSX Firewall settings for Tiger (similar instructions.)