Have you tried an empty *.gma in case it's just looking for the file name and not actually verifying it? This was noticed in a [Only registered and activated users can see links. ] that the unit was just looking for the file name only and one from a different ID unit worked. Loly created an empty file for testing but i don't think anyone reported back about it:
Spoiler: Download file
http://www2.zippyshare.com/v/86601993/file.html