That kind of makes sense.

http://websurfaces.co.uk/2012/07/31/this-package-wasnt-built-for-the-current-version-of-windows-install-the-current-version-of-windows-and-build-the-package-again/

I have to say that I haven't been impressed with the way that Windows 8 App store submissions have been handled. 

Talk about 'dance monkey boy'