Hello, I am trying to run the NDR model but I keep getting this error

UFuncTypeError: ufunc ‘subtract’ did not contain a loop with signature matching types (dtype(’<U3’), dtype(’<U3’)) -> dtype(’<U3’)

I do obtain some intermediate files thoug. Any idea? Many many thanks, help really appreciated! Here’s the log:

InVEST-Nutrient-Delivery-Ratio-Model-(NDR)-log-2020-06-09–10_21_05.txt (3.4 KB)