Many ppl have taken the time to help you, and your reaction is name calling and insults. Just because you dont like the answers ppl who took the time to try to help you gave, is no reason to be rude, and we wont tolerate that here.
You were told that it is indeed possible and quite common for schools and businesses to completely block access to IRC. It was suggested you speak to the sysadmin at your school to determine if that is indeed the fact (which your posts indicate it is). If they have, there are prolly not any holes, and any there are would be something we arent going to help you find (and would not be as simple as a server port). We are here to help with mIRC probs, not circumvent your schools policies. You did indeed ask for help/holes in getting around it, specifically: are there any other ports you could try.
You said you used mIRC for some time without probs, then your school instituted changes and now it doesnt work. The error you got is client side, which means on your end, the schools network/firewalls, not mIRC or the IRC network/protocol. We could only guess at what steps they took and to what extent, THEY are the ppl you need to be talking to for information.