Fatal error: Call to a member function getItems() on a non-object in

When I enable this plg for emirald

Emerald Subscriptions Granter

I get this error when I tray to create new user or shuld edit enny user from backstages

to joomla ver 3

Fatal error: Call to a member function getItems() on a non-object in /home/u/administrator/components/com_users/models/user.php on line 662

but when I disable this I can edit and create new user how to fix this ??

Plugin 9.7