Any specific reason for switching from Mathcad to Prime? After all its a step backward.
If you are happy with the Mathcad 15 sheet, why don't you try using the converter to turn it into a Prime sheet?
I don't see the function F() you are talking about but maybe you should lookup "vectorization" in the help.
From the first error message (the one in the collapsed region where you try to turn the range into a vector) it looks like you are using just Prime Express. Programming (as many other things) is seen as a premium feature and is not available in Prime Express.
Anyway I worked a bit through your file and marked some regions in red. Hope it helps.