mIRC will not work on a mobile phone. That is not possible.
Remember that you do not connect to 'mIRC' you connect 'IRC'. There are different clients all over the Internet, mIRC just happens to be the most popular one, but it is not the same as IRC
There are a couple of clients I've heard of out there that let you connect to IRC via your mobile phone. One of them is
Wireless IRC which seems to be compatible with the Nokia 6600.
I have absolutely no idea how that client works, it's features or what error messages it may or may not display. However, if it displays general IRC error messages, which it should, then they are the same for a lot of IRC clients. You might try looking in the
Common IRC Errors thread for some help on what they mean, and using the Forum's
Search feature to find out how to solve them.
As you are not using mIRC however (and these message boards are for mIRC support) I strongly recommend contacting the author of Wireless IRC for help.
Best of luck!
Regards,