There, I fixed it.
I'm still not sure why this makes a difference but I fixed the issue by removing the 4 large data files (2+GB) that make up the distributed data from the program setup and put only those files in a separate data update.
BTW - the single install project for this creates the 8 different versions of the software and 2 versions of the data. The data install is called at the end of the program install if the user selects to copy the data.