So I bought SINS when it came out and I played it for quite a while, but due to some unfortunate circumstances a few months ago I didn't have much time to play it, so I uninstalled the game and stardock. Now I have the time again (yay!) to play it and I was going to set it up this afternoon after work, but no go

I heard about impulse and that is how stardock is distributing the games now so I downloaded it, installed it fine, logged in with my old stardock account and it said I had SINS available to install. But when I click "Install" it gives me "This program is not compatible with your current operating system." This makes no sense at all because I had it running on this same exact computer before (no reformats or anything since) and now it won't let me install it. Anyone have any ideas as to why this is?
Rig Specs:
Windows XPx64 Pro SP2
Core2Duo E6600
(2x) ATI Radeon X1900
4GB of Corsair DDR2