Saved pages are missing in the list…

…and I can also not add any new pages to my favorites. The add link changes into the remove link but the pages do not appear in the favorite post list. It worked before the plugin update from 1.5.7 to 1.5.8 and works with an older version (1.5.2).

http://kmeducationhub.de/

http://wordpress.org/extend/plugins/wp-favorite-posts/