Ok a few things I can see....
Firstly your ZoneAlarm security could be stopping your connection...
So there are two options..
1. Port Forward ZoneAlarm if you are using Pro...
Port Forwarding for the Dlink DI-604 (this should read ZoneAlarm, it is for ZA)
2. Try this fix, as silly as it sounds it works...
http://www.gnutellaforums.com/281366-post6.html
The second thing is your router, the F5D9230-4 has a Nat Firewall, so i'm guessing the F5D9230-D will have one as well..The instructions to Port Forward should be similar...
Port Forwarding for the Belkin F5D9230-4
Then there's your ISP Virgin are known to block your bandwidth during peak times if your a p2p user...
Traffic management