Figured out the problem. The first line in subscriptoins.php is not correct. I commented out the org line and replaced it with a working line. Its a BUG!
// Require the library
// require ("/home/www/html/ubbthreads/main.inc.php");
require ("../../includes/main.inc.php");
require ("$thispath/languages/{$myprefs['language']}/subscriptions.php");
$html = new html;
$mailer = new mailer;
// ----------------------------------------------
