Please dont post the same question multiple times, it creates confusion in those trying to help.
Just a little info to help with asking questions:
-there is a difference between joining channels on a network and connecting to a network by its servers to begin with. You have to connect to a server before you can join a channel on that network. The msg you recieved is a network/server connection error.
-mIRC is software used to IRC (internet relay chat). Using it, you connect to any of many networks by way of the servers each has. Once you connect, each network has its own channels. mIRC itself isnt involved with the networks, their servers, the channels they have/allow, who is in those channels or their policies
See the replies on your various other posts.