I am having a strange error while opening event categories from outside the calendar or through the event preview widget and while not been logged in, there are two error messages.
take a look at http://www.esport-calendar.de
I already have reinstalled the all in one event calendar.
I also have deactivated all other plugins, still...
Warning: array_combine() [function.array-combine]: Both parameters should have at least 1 element in /homepages/43/d197569055/htdocs/esport-calendar/wp-content/plugins/all-in-one-event-calendar/app/model/class-ai1ec-settings.php on line 902
Warning: array_diff() [function.array-diff]: Argument #1 is not an array in /homepages/43/d197569055/htdocs/esport-calendar/wp-content/plugins/all-in-one-event-calendar/app/controller/class-ai1ec-calendar-controller.php on line 145