Some Bugs displaying Events

Hey there,

I’m having problems on one of our sites with the Plugin.
It doesn’t display the events correct in frontend. It only displays one single event in the first week of every month instead of different events in different categories stretching over the whole month. Additionally the category-select-buttons don’t work.
I’m gonna provide provide the link here:
http://www.palatin.de/saisonkalender/
Events start from January 2014.

Thx,
Chris

http://wordpress.org/plugins/ajax-event-calendar/