fEmail

I'm trying to send mail by smt with attachement, local it's working but on the server don't i print email object and on attachement appear one message, can anybody know what is that?

fEmail Object
(
    [attachments:private] => Array
        (
            [licenta.llv] => Array
                (
                    [mime-type] => text/plain
                    [contents] => Failed
Missing or invalid parameter 'custid' 
                )

        )