I was able to build Gridview solution by changing the reference to DataAnnotation DLL from Silverlight 5. I have just copied the resulting dll to the folder generated by the batch file. I hope this is fine.
If I comment out the Key resource in App.xaml, it throws an error saying that the current version of assembly can only be use with the "Application name". But if I just declare the resource and not put anything or random string in the key resource, it doesn't complain. Is this meant to happen? Isn't this string be compared to the one that was used when building from source?