From looking at your pictures, it's failing because when the instantiation of the child pcell is happening, it is expecting a string, not a float - although the error message appears to say that it's expecting 2e-12 (not sure why that is). I see that the length is being passed as a string - so I'd have expected the width to be the same type.
So my guess (without seeing the actual data) is that you should change the type of width to be a string, and then make your stepping distance in the repetitions equal to cdfParseFloatString(width)/2 .
If this doesn't help - I'd suggest going via customer support - this kind of thing is much easier if we can see the actual data. As a colleague of mine used to say - "a picture is worth a thousand words, but a database is worth a million"