CMS Function works in Forum but undefined in CMS
 

I am using a customization to pull the title of the latest entry in an external blog. See http://www.vbulletin.org/forum/showthread.php?t=234254 for details

This works fine and generates no errors in the Forum.

However, I've now enabled the CMS and when I do that and try to leave a comment I get this error:

PHP Code:
Fatal error: Call to undefined function CarpCacheShow() in /path/to/forum/includes/class_postbit.php(277) : eval()d code on line 2

I assume this means something is not declared properly for the CMS.

The function in question is called in a plugin using the postbit_display_start hook:

PHP Code:
ob_start();
CarpCacheShow($post[field6]);
$blogentry = ob_get_contents();
ob_end_clean();
vB_Template::preRegister('postbit',array('blogentry' => $blogentry));

What do I need to add/change to get CMS to "see" and process this?