note 60583 added to function.header

I have a php script that creates an excel file from information stored in our data base and the users can download it dinamically (using Header function). At the begining everything was ok, but after running windows update (WinXP) this script fail. I tried everything, changing headers, disabling windows firewall, setting IE security to LOW, everything!!! but not work in some PCs. If someone know what is going on please help me. //******* headers ****** Header('Content-Transfer-Encoding: binary'); Header('Content-Disposition: attachment; filename="' . $destino . '"'); Header("Content-type: application/vnd.ms-excel"); readfile("$location"); unlink ("$location"); ---- Manual Page -- http://www.php.net/manual/en/function.header.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+60583 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+60583&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+60583&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+60583&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+60583&report=yes&reason=useless Delete: non-english -- http://master.php.net/manage/user-notes.php?action=delete+60583&report=yes&reason=non-english Delete: already in docs -- http://master.php.net/manage/user-notes.php?action=delete+60583&report=yes&reason=already+in+docs Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+60583&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+60583&report=yes Search -- http://master.php.net/manage/user-notes.php