In a new Hotcakes 3.2.0 + DNN 8 instance, I'm encountering a problem in checkout when attempting to enter a Promotional Coupon Code on a testing order.

At first I thought that it was an error with the AddCoupon being broken or missing as the console shows an error loading
domainname.com/DesktopModules/Hotcakes/API/mvc/cart/addcoupon
but loading it with the proper info passed to it, it's showing a .net error message of

[DivideByZeroException: Attempted to divide by zero.]
System.Decimal.FCallDivide(Decimal& d1, Decimal& d2) +0
System.Decimal.op_Division(Decimal d1, Decimal d2) +17
Hotcakes.Commerce.Orders.OrderCalculator.TaxItems(List`1 items, IAddress billingAddress, IAddress shippingAddress, Decimal totalOrderDiscounts) +428
Hotcakes.Commerce.Orders.OrderCalculator.TaxOrder(Order order) +121
Hotcakes.Commerce.Orders.OrderCalculator.CalculateTaxes(Order order) +112
Hotcakes.Commerce.Orders.OrderCalculator.Calculate(Order order) +188
Hotcakes.Commerce.HotcakesApplication.CalculateOrderAndSave(Order o) +39
Hotcakes.Modules.Core.Controllers.CartController.AddCoupon() +118

... etc in the StackTrace

My first thought is that there must be something missing in the setup of the store such as tax or shipping cost values, but having checked on that (all tax and shipping and setup in the product for tax values were present), I then went in and filled in every field from handling to others and gave all values. No difference, still divide by zero error.

Anyone else run into this issue during setup and testing of a Hotcakes site and coupon?

Any suggestions for what to test/check next?