Many schools and businesses block the ports needed to use dcc, in fact many dont allow access to IRC at all. You see, what you refer to as "the joys of DCC getting and sending" includes sharing files that are illegal to share, in violation of copywrite laws. Its also the fast track to getting assorted viruses and trojans that can cause horrendous problems to not just your puter, but the entire network at your school (not to mention the IRC networks and other ppl you send it on to). Obviously, you will need to take the matter of ports up with your techsupport.
mIRC wasnt designed for mass filesharing. The dcc protocol is very basic and intended to be used for the occasional use amongst friends, like to send pictures or text files they are working on together
