Filemaker Go does not like Preview and unfortunately Filemaker Pro can insert the Preview function in a script which causes Go to hiccup and produce an error and mesage. It seems to not insert the offending code in Filemaker Pro 12.
The Report List View can be viewed in Go or Pro but it needs to be sorted to be viewed just as it must be sorted to be printed.
So your script should have:
Go to layout report list
Sort Records (sort in order of the sub-summary parts)
Now it wll look nice in Go or Pro.