I've tried the mod and what you suggested a couple of times but keep getting an error.
You basically want me to add the second set of code below the first one, right?
so, find
define('TEMPLATE_PATH', ROOT_PATH.TEMPLATE_DIR."/".$user_template);
and below it add
if ($user_info['user_level'] >= ADMIN && isset($_GET['tpl']) && !empty($_GET['tpl']) && @is_dir(ROOT_PATH.TEMPLATE_DIR."/".$_GET['tpl']))
{
$user_template = $_GET['tpl'];
}