When importing events from the Active Data Calendar to the All-in-One Event Calendar for WordPress, there is a communication issue between these two software applications which causes all-day events to be incorrect by one entire day in the All-in-One Event Calendar. However, there is a way to prevent this error from occurring. Before exporting from the Active Data Calendar, change all of the all-day events to have Start and End times. So for example, if an event only occurs during business hours, make the event show as 8am to 5pm. If an event is truly an all-day event, make the event show as 12:01am to 11:59pm. This will cause the events to display correctly in the All-in-One Event Calendar.