"Register with Facebook" button spits error with CoursePress/Membership

Warning: array_key_exists() expects parameter 2 to be array, null given in D:\home\MYURL.com\wwwroot\me\wp-content\plugins\coursepress\includes\classes\class.shortcodes.php on line 2789

The above error results upon clicking on the "Register with Facebook" button

Please see http://goo.gl/rPPsph