That's weird.
I have just checked the file that you downloaded with my Norton anti-virus, and it says that there is no suspicious stuff in there.
But just to be sure, I have also substituted the previous downloadable file with a new one (I generated this one from the engine, as I did with the previous one).
I checked this new file with my anti-virus as well, and it seems to be fine.
Can you try downloading this new version to see if you have the same problem again?
Did you also have this problem while downloading any of my other games?