The only thing I can think of is that the network or server is executing a shun state on you because your hostname doesnt resolve, kinda lame if that what is happening, my hosname dont always resolve either depending on network and I connect join and privmsg just fine. I can only assume that the problem lies server side and that either the dns caching isnt working or it just cannot resolve. As for the possible shun I really never thought any network would use a dumb response to an unresolved hostname but its IRC and many networks do dumb things I guess. Maybe a visit to the networks website and an email to the admins of said network could shed more light on this problem?
Good luck
