Whenever I try to login I just get a "Connecting" message and, after a long while, a timeout message. Could this problem be caused because I am connecting via a local network? I am running Vendetta on a PowerMac G4 with OSX jaguar - system firewall turned off.

It definitely sounds like a firewall error. What's the firewall on your router set to do?

I am not sure, but I'll check with sysadm.