2 almost identical plug-ins, one is working other is not.

[webmaster74]

I add an external php file to the common-template "header" of each style
$includedphpheader
and this works smoothly.

In the same way, I added $includedineverypost in the postbit template.
and a plug-in hooked to Product : vBulletin
plug-in title ineverypost
Hook global_start
Plugin PHP Code
ob_start();
include('/home/domain/public_html/php/includes/ineverypost.inc.php');
$includedineverypost = ob_get_contents();
ob_end_clean();
Plugin is Active YES
but $includedphpheader is not being parsed.
What am I missing?