I joined an IRC channel, and it said there was a person with the same nick as I, but there wasn't! I guess that the person "@Q" caused this bug. http://i32.tinypic.com/2ish153.png
No, it's because the client joins on the quakenet, and the quakenet is already full of users who use many nicks
So the nick needn't be in the cs2d channel but is used.
Instead use a nick with numbers at the end