Please do not use the 'Notify Moderator' button to get attention to your post, moderators are not the only ones that can answer your posts and it doesn't get you answered any faster.
The message you're seeing means you've been banned from the network for spamming (unsolicited advertising). You may have been doing it accidentally if you're infected with an "mIRC virus", or the ban may be placed on your entire ISP and so isn't aimed at you directly but is affecting you anyway.
The only thing you can do is wait until October 6th 2007 or contact the network's IRC Operators for assistance. It has nothing to do with mIRC, you would get the same result using any IRC client. Check out the network's website for contact details. Alternatively, use another network altogether.