PHP include plugin not working on CMS pages

[DesignWerks]

I created a global_start plugin with the following code and placed the

{vb:raw includedphp_main}

in the header. It works fine on the Forum and Blog pages but does not appear on the home page or any other CMS pages.

ob_start();
   include('global_mainphoto.php');
   $includedphp_main = ob_get_contents();
ob_end_clean();

$preRegister['includedphp_main'] = $includedphp_main;
vB_Template::preRegister('header', $preRegister);