no Button for User rating

Hi,
i have activated the user rating function in the admin menue (library settings-advanced-uservotes, but i cant see the rating-button and im getting the following error message on a whitescreen:

: string(7) “in here” Warning: Cannot modify header information – headers already sent by (output started at /customers/b/b/2/xxx/httpd.www/wald/wp-content/plugins/link-library/link-library-admin.php:2313) in /customers/b/b/2/xxxe/httpd.www/wald/wp-includes/pluggable.php on line 1296 Warning: Cannot modify header information – headers already sent by (output started at /customers/b/b/2/xxx/httpd.www/wald/wp-content/plugins/link-library/link-library-admin.php:2313) in /customers/b/b/2/xxx/httpd.www/wald/wp-includes/pluggable.php on line 1299

Is there another point in the admin menue that i have to adjust ?

The page I need help with: [log in to see the link]