FYI: You don't connect to mIRC, you use mIRC to connect to an IRC server.
"Unauthorized connection" means that that server does not allow connections from your IP/host/country (common on IRCnet where they like you to use a local server).
I haven't seen the "too many host connections(global)," but "too many user connections (global)" means that too many people from your host/IP are connected to that network. This probably means that other people are also using their GPRS connection to connect and that your ISP does not give each user a unique IP.
You should be able to get on IRC, you're just not having much luck with the servers/networks you're trying.
