I'm having the exact same issue. My PF USB stick just arrived today, and I'm living with the frustration of trying to get it to work without having to download >60GB.
I've looked through the files on the stick, and found that the following are corrupt or unreadable:
Aversion
EULA.html
InstallerConfig
Name
SDX-Doc.pdf
SDX-Keys.pdf
compoundpresetconf
instrumentgroups
kitconf
micconf
uberconf
However, the Sounds directory and all the *.obw files therein are readable, as is the GM-padconf file. I've also tried the Disk Utility 'First Aid' on the USB stick, but it wasn't able to help out.
So I've copied what I can to the /Library directory in the support article, and hope to be able to get the Product Manager to recognize, authorize, and update my new ProgressiveFoundry. I really hope I don't need to download 64GB to pull off that trick!
Any words of wisdom are most welcome.