Wordpress Update "Fatal Error" message

[CassieLadd]

Hello -

one of my former clients performed the automatic update for wordpress and is subsequently getting the following error message when she tries to access the login to the dashboard:

Fatal error: Class 'Genesis_Admin_Basic' not found in /homepages/7/d352737780/htdocs/wp-content/plugins/genesis-simple-sidebars/includes/admin.php on line 14

I've looked on line 14 - it says:

class Genesis_Simple_Sidebars_Admin extends Genesis_Admin_Basic {

I'm not sure how I need to fix this in order to give her access again.

Please assist.

Thanks,
Cassie