Pathing Issue

Inside cmsms-contact-form-builder/inc/form-builder-operator.php you do:

$parse_uri = explode('wp-content', $_SERVER['SCRIPT_FILENAME']);
require_once($parse_uri[0] . 'wp-load.php');
require_once($parse_uri[0] . 'wp-admin/includes/admin.php');

The better way to do this is to use WordPress built in ABSPATH define. The plugin breaks on installs where WordPress core is in a subfolder. Changing your code to the following will ensure it works on any WP install:

require_once( ABSPATH . 'wp-load.php');
require_once( ABSPATH . 'wp-admin/includes/admin.php');

This is also an issue in your cmsms-content-composer plugin as well.