I am struggling to activate plugins. I installed members only, trusted only, User Access Manager and Sidebar Login successfully but when I click on activate plugin I receive the following message: Fatal error: Class 'WP_Plugins_List_Table' not found in /home/u01124512106/public_html/workshop/wp-admin/includes/list-table.php on line 51.
This message also appears when I click on "plugins" and on "installed plugins". Can anyone help? Many thanks!