Google didn't find anything for Army Men 2.1
Where did you download it from?
It's possible that it is not compatible with Vista, but the web site you got it from should tell you that.
Mark
I recently bought, and downloaded the pc game Army Men 2.1 . After download, and when I attempted to install, it installed all right, but when I tried to open program, a Windows dialog box opened, saying the game had stopped working. I took program out, and reinstalled 3 times, with the same result. Is there a trick to making it work with Vista, or is the game too old for my system? Any tech feedback would be appreciated.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic