When I went to create a new coupon today, I forgot to create a start date before attempting to save. Naturally, the save errored out, telling me to enter a start date. Using the calendar drop-down, I created a start date in the future. Hit save, and still got the error. Tried several different dates, including today. Same thing. Finally got around it by creating a new coupon and doing it right the first time.
I've run into similar bugs with AWO before with different things. Yuck.