if you're able to share your code, we can help troubleshoot. That said, I have submitted a bug because while it works in the calculation editor, my array calculation errors out on the actual form.
I heard a rumor at Summit that right now that the functionality is cosmetic and was unlocked in order to make a space for future functionality. So even getting a result, I wouldn't expect to be able to do much of anything with that result for a while.