How did you managed to download the app to your desktop ? the website will prompt you to connect your camera every time you want to purchase. Just spoke to Sony Singapore and they told me that the problem came since last week or so.
They said it will work in 7 days time. If its not fixed, I'll sell my Sony and get something else. Plenty of good stuff out there.
I hope Sony is reading this. This should never happened in the first place.