Events not showing in FullCalender with IE9

When I go to view my event in Full Calender on my site via IE9 none are visble.
I’ve installed Full Calender alongside Event Manager and the events are OK when viewed in the basic calender
Also, when I view my web site with Safari or Chrome I see the events in the Full Calender.

Any thoughts?

https://www.ads-software.com/extend/plugins/wp-fullcalendar/