You can find descriptions of various errors at http://support.ipswitch.com/kb/WSK-19980721-EM01.htm

Have you tried checking the network's website for a current list of servers?

As far as your router/firewall, in general be sure its allowing mIRC and the various server ports (6660-6669,7000-7001 and 113 for identd and also enable identd in mIRC's options) and that you have done whatever port forwarding is needed

ParaBrat @#mIRCAide DALnet