Have a look at the firewall link & at the very bottom of that page it'll link to your firewall. ALlow LW & either Gnutella or javaw.exe
Sorry I don't have experience with that so I can't be more specific.
A of interest & B
There's port forwarding details for
Port Forwarding for the BT Voyager 205 ADSL Route but not for the BT 100 so yours might not need it.