User Levels Capabilities.

To remove error message had to update the following to user “manage_options” rather than the old “level” numbers.

function adt_admin_actions() {

    add_users_page("Active Directory Thumbnails Options", "Active Directory Thumbnails", "manage_options", "active-directory-thumbnails", "adt_admin");

}

http://wordpress.org/plugins/active-directory-thumbnails/