[Zope] script returns error

[Raymond Norton]

In the Tutorial,Under "Coding Logic with Scripts: I have successfully
created the example for calculating compound interest. When I submit the
form with a value of  amount = 1000, rate = 6, periods = 12, years = 10, I
get this error.

Error Type: NameError
Error Value: global name 'calculateCompoundingInterest' is not defined

Being new I am not sure what is wrong. I am continuing on, but would like to
get this to work.



Raymond