Problem with menu configuration

Hi, when I got the plugin active, the menu (/wp-admin/nav-menus.php) is not fully loading.
Error message is:

Fatal error: Call to a member function render_multi_rating() on a non-object in /wp-content/plugins/gd-star-rating/code/class.php on line 396

http://ww.wp.xz.cn/extend/plugins/gd-star-rating/