I'm also using a personal firewall on my PC.

I allowed:

- incoming TCP from all addresses, ports 1024-65535 (all but well-known ports) to my address, port 6346

- outgoing TCP from my address, ports 1024-5000 (temporary range) to all addresses, port 6346-6355


This works fine, except for some computers that have their gnutella port set to something unusual (not in 6346-6355), consequentially my Limewire is not be able to connect to them. But i don't feel seriously restricted by excluding a few hosts.
To avoid filling up your firewall log, on the connections tab remove all discovered hosts with ports number other then 6346-6355 (only necessary once after installtion).

Hope it helps
M.