--- a/gameServer/Actions.hs	Sun Oct 23 09:01:53 2011 +0200
+++ b/gameServer/Actions.hs	Sun Oct 23 11:37:52 2011 +0400
@@ -340,7 +340,7 @@
     h <- client's host
     p <- client's clientProto
     uid <- client's clUID
-    haveSameNick <- liftM (not . null . tail . filter (\c -> nick c == n)) allClientsS
+    haveSameNick <- liftM (not . null . tail . filter (\c -> caseInsensitiveCompare (nick c) n)) allClientsS
     if haveSameNick then
         if p < 38 then
             mapM_ processAction [ByeClient "Nickname is already in use", removeNick]