You cannot use a comparison of the digits buffer that contains none or# against a specific numeric value that is not a variable. The goto test will always fail and fall through to the next step. For example:

2. goto step 1 if digits <= 0 [will branch to step 1 only if digits contains a 0]
3. …  [this step reached if digits contains none, # or a digit between 1 to 9]

You cannot directly enter none or # as a threshold value with comparators other than = or <>.