Using vBulletin class is requiring user log-in

[JeremyAM]

I'm writing a very simple script to connect our vbulletin accounts with accounts in our own system. The problem I'm having though is that merely by including the vbulletin class files, so i can use some functions, it's requiring that you be logged into an account with permission to view the forum.

in practice we'll have the script on our forum server, and use cUrl to from our main server to run it. we'll pass some values to the script in $_GET. when i test it out by simply going to the script in my browser, i simply get a vbulletin "not logged in / you don't have permission" screen.
if i give "Can View Forum" permissions to "Unregistered / Not Logged In" group, then it works.

is there a way around this? i don't want unregistered users to be able to view the forum.

here is first few lines of code:

PHP Code:

<?php
//==========================================================
// class vBulletin-Bridge
// See README, INSTALL for installation/config/usage instructions
// Released under the new BSD license.
// Copyright (c) 2009, Sam Cleaver (Beaver6813) All rights reserved.
//==========================================================

define('FORUMPATH', 'redacted'); // path to your forum

define('REGISTERED_USERGROUP', 2); // typical default for registered users
define('BANNED_USERGROUP', 8); // typical default for banned (was 19)
define('NOACTIVATION_USERGROUP', 3); // typical default for user awaiting activation
define('PERMANENT_COOKIE', false); // false=session cookies (recommended)

// end of configuration stuff
//==========================================================
define('THIS_SCRIPT', __FILE__);
$cwd = getcwd();
chdir(FORUMPATH);
//echo('this will echo fine');
require_once('./global.php');
//echo('but we never get this far');
require_once('./includes/init.php'); // includes class_core.php
require_once('./includes/class_dm.php'); // for class_dm_user.php
require_once('./includes/class_dm_user.php'); // for user functions
require_once('./includes/functions.php'); // vbsetcookie etc.
//require_once('./includes/functions_login.php'); // process login/logout
require_once('./includes/functions_user.php'); // enable us to sort out activation

....

might be useful to know that we're using the vbulletin classes mainly to get info on an account and to activate the account using the username and signup activation key.