Since the 19.5 one is fully functional (yes?) could it be some sort of permissions error w/ Windows 8 and your user account.
You have the 20.0 folder in your Documents folder, the 19.5 in the Downloads (which generally has full read/write access).
Cut/paste the 20.0 folder from its current location to the same place as the 19.5 and see if it works. If it does, good luck figuring out why a User directory like My Documents doesn't have full permissions, that's fucked.