Direct from the help file:
$comcall() uses the same format as $com() apart from the alias. It is multi-threaded so it will not halt the script and will call the specified alias once the call returns.
Note: If $comcall() fails when calling an object and $com() does not, this means that the object is not compatible with the threading model of mIRC, so $com() must be used. You can check the $comerr value in the alias to determine if a $comcall() failed or not.
So, if you're using the same format and it's failing, it probably can't be done. That or your format needs work. Can you paste what you're trying to use?
