VBulletin: Call to a member function of non object

require_once  $_SERVER['DOCUMENT_ROOT'].'/forums/global.php';
                require_once  $_SERVER['DOCUMENT_ROOT'].'/forums/includes/functions_login.php';

PHP:

I am trying to include the VBulletin functions into one of my functions thats called by an include from the main script.

Its like:

1. User hits: index.php
2. Index.php loads a loadconfig.php
3. Load config loads all my files including a /functions/basic.php
4. In the basic function script it has all my sites functions. I have one that loads the VBulletin variables and config to my script but I get Call to a member function of non object. Why is this?

I have tried a lot of things.