Reply To: Availability Calender not showing up

I have the same problem.
The Javascript Console of Chrome replies with:

TypeError: Cannot read property ‘value’ of undefined [https://piratentechnik.de/wp-content/plugins/easyreservations/js/ajax/send_calendar.js?ver=3.2.4:89]

That line says:
var tsecurity = document.CalendarFormular.calendarnonce.value;

My code on the page is as follows:
[easy_calendar resource=”1138″ width=”100″ style=”1″ price=”0″]

My WP version is 3.6, ER version is 3.2.4.

Any help would be greatly appreciated.