Supporter not forcing the supporter page

For some reason supporter isn’t forcing the supporter page when the I’m interested radio is checked.

It’s working on a test site, but not the one I want it on. They’re on different servers at different hosting companies if that makes a difference. The one that isn’t working is with psek.

I found this code which looks like it is meant to handle this:

function supporter_signup_redirect() {

//dismiss redirect if link is clicked or paid
if (isset($_GET['supporter_dismiss']) || is_supporter())
update_option('supporter_signed_up', 0);

//force to supporter page
if (get_option('supporter_signed_up')) {
//if not on supporter page
if (strpos($_SERVER['PHP_SELF'],'supporter.php')===false) {
$url = admin_url('supporter.php');
wp_redirect($url);
exit();
} else { //remove menus

global $menu, $submenu;
$menu = array();
$submenu = array();
add_action('admin_head', 'supporter_signup_css');
add_filter('favorite_actions', 'supporter_signup_actions');
//add_action('supporter_output_before', 'supporter_signup_dismiss');
add_action('supporter_output_after', 'supporter_signup_dismiss');
}
}
}

Any thoughts?