php imap functions problem

Hello NG Please excuse my bad english because I come from austria. I hope you understand me... I have searched in the NG and in internet and don't found an answer to my php problem: When I use the imap functions with php all looks like good but when I will get the body or structure from an email I get an error. my Code looks like this: ------------------------- $mbox = imap_open( {localhost:143/imap/notls}INBOX , username , password , OP_HALFOPEN ); $structure = imap_fetchstructure($mbox, msgnum ); The Error ( Warning ): ---------------------- Warning: imap_fetchstructure(): Bad message number in (...) on line (...) I dont't think that the Message number is really the problem because i tested also other numbers. I hope anybody can help me! Thanks Markus