This error will appear when you are trying to create a schedule that in some way overlaps a previously created schedule.
1. Check to make sure your Start Dates and End Dates are not the same as any previous schedule created. If you do have overlapping dates, go to the next step.
2. Now check to make sure the overlapping dates do not have any time overlaps.
Note: A Schedule set to play from 5:00am to 1:00pm should be set like this:
Start time: 05 00 End time: 12 59