I bit the bullet and purchased the $20 Rebellion game and it works fine. Conspiracy theorists would say this is deliberate to push you into buying the latest and greatest instead of the old game pack.
I hope that this is an anomaly for Stardock and I do remember playing a very well-done Sins game a while ago, so I will give them the benefit of the doubt here. I think you are on to something about the installer - my installation is 64mb on the XP and the Win7 machines (I'm near those atm), which is obviously too small. It is amusing/annoying that the 1.1gb or so installer results in a 64mb installation. XP, Win7, Win8 - ATI, nVidia, Intel graphics - all fail. I did fre