Try changing your hostname lookup method:

ALT+O > Connect > Local Info

Under 'on connect, always get' make sure 'Local Host' is checked and try the 'server' lookup method. If that doesn't work, try the 'Normal' lookup method.

You can also try other networks/servers and see if you get the same error message, for example irc.quakenet.org, irc.undernet.org or irc.dal.net. As far as I know, that isn't a usual connection error message, you might get that from the server messages though (by default they're brown). If that is the case, then it is more likely that you shouldn't get the error message with other servers.

If you recently installed/enabled a firewall, disable it and try again. For information about how to enable/disable the Windows XP Personal Firewall, click here. The same goes for Routers, if you recently installed one, disconnect it from the machine.

Finally, see if there are other similar problems to do with this by using the Search feature.

G'luck.

Regards,

Mentality/Chris