error on registration

Just activated this plugin and it looks just the ticket. cle-france.bell-computing.com

But I get the following message embmazoned across the top of my screen when I click Register. Does it matter? And if it isn’t important, how do I suppress it? I have debug and debug display set false in my wp-config.

Warning: Creating default object from empty value in /srv/users/serverpilot/apps/wordpress/public/wp-content/plugins/network-subsite-user-registration/template/page-signup-wp47.php on line 44

The page I need help with: [log in to see the link]