Unless that is some message from an unusual ircd, it isn't a message that you should be getting. mIRC doesn't tell you that and no servers I've seen tell you anything like that either. It looks to me like a script. Try typing: /remote off
After that, try changing your nick and see if you still get that message. You can also enable debug mode: /debug @debug
After enabling that, try to change your nick and then use /debug off and copy/paste what is in the @debug window here.
