Multi-Domain Plugin Issues


So I'm trying to install the Multi-Domain plugin.

encountered several issue:
1) trying to install via the WPMU DEV Dashboard doesn't work.. no big deal!!
2) manually installed as directed, it doesn's show on the installed plugins area of my WP and doesn't show here as an option!!
3) now the 'Domain Mappings' plugin shows a [Please edit your /home3/XXXX/public_html/wp-config.php and move the line define( 'SUNRISE', 'on' ); above the last require_once() in that file or make sure you updated sunrise.php.]

here's the relevant part of the wp-config.php

define('SUNRISE', 'on');
/** Sets up WordPress vars and included files. */
require_once(ABSPATH . 'wp-settings.php');

-- off course, I create the wp-content/mu-plugins/multi-domains-files & copy the DM_sunrise.php to the /wp-content/sunrise.php

so now sure what I'm doing wrong .. can you help please??