That's because AmIRC isn't able to get the host IP from the server... If you use a DynDNS Account, it should work fine.
WookieChat works quite nice, but the handling of AmIRC is still better... But as a new user, there is little chance to get registered...
A few time ago, I lost my AmIRC keyfile, and Oliver Wagner mailt me my keyfile. Maybe he's still able to create Keys?
His mail-address still exists.