[Bernd]

Ok, thanks for explaining. I'll try that one and post the results.

				// check if the user has already OK'd the points removal
				if ($vbulletin->options['vbbux_attachconfirmpage'] && ($_GET['download'] != '1'))

is the only place in vbplaza_attachment_start.php where "POST" is located. Doesn't seem like that's causing the issue though. To be certain i have replaced it with "GET", but a link with STC=1 will still download without showing the vbplaza download attachment template or substracting the points.

Could there be a plugin hooked into attachment somewhere that contains POST? Still seems to be there's something wrong in the above mentioned php.