Check for an ip mismatch by typing /dns yournickhere   and  then typing //say $ip and compare the two. If they arent the same, type /localinfo -u  and then try to DCC send.
Thanks A LOT.  This just paragraph solved almost 3 years of ignorance and 'messing stuff up'.
Really, thank you a lot.  I think this should be included in mIRC's options (somehow).  Thanks again for your great support.