Hello All and Help! (Hope this makes sence)

=Sum2DProduct(ProfitMons,C$8,ProfitCodes,$BD11,Pro fit)
All ranges are within the same file.

I have the above custom function that works well when the file is active.
However, when a different file is active then the custom function returns a
value of '0'.

I'm guessing the function isn't referencing anything to do with the file it
is in, only the ranges selected for the funtion. And is applying itself to
the wrong active file.

How do I get the function to apply itself to the file it belongs to.

Thanks