Access vBulletin Users from CMS Made Simple?

[pharside]

I would like to use the users from vBulletin which is in the same site as our CMS Made Simple site, but I'm running into issues.

I'm using the following code:
$curdir = getcwd ();
chdir('/path/to/form');
require_once('./global.php');
chdir ($curdir);

At the start of the code (I run into issues when I embed it into a module, something about calling it from a php object that causes an error in functions (query_first_slave)), but something that it's doing is playing havoc with CMS Made Simple and it's losing the ability to resolve pages.

Is it possible that it's clearing the $_GET?

Any ideas?