Well, if a script error occurs, when mIRC looks for :error, if the label of a goto appears twice while looking for this :error label, mIRC will report a duplicate label error instead of the original error, it took quite some times to figure this one out grin !
Code:
alias test {
echo -a
:test
:test
}


Looking for a good help channel about mIRC? Check #mircscripting @ irc.swiftirc.net