I've now tried 2 MSNP8-compatible scripts and both have the same problem.
1 specific MSN account works
and the other one doesn't.
While using MSN Messenger 6.1 they both work.
In MSN for mIRC, it goes wrong at:
if (!$com(auth,Send,1)) { return }
if ($com(auth,GetResponseHeader,1,bstr,authentication-info)) {