I found the problem. It was incorrect Transaction Type in 2 of my 3 Tax Templates. I have 3 taxes:
T0: 0% Sales Transaction
T12: 12% Payment Transaction
T15: 15% Payment Transaction
I corrected T12 and T15 to use Sales Transaction, and no more crash:
T0: 0% Sales Transaction
T12: 12% Sales Transaction
T15: 15% Sales Transaction
But you might want to add a check/catch for this...
Thanks,
Q