I'm having the exact same problem that is described in this topic: http://social.answers.microsoft.com/Forums/en-US/vistagaming/thread/f15edea1-f88f-492e-bb42-4db2b06fdf05
My error message is: "This version of the file is not compatible with the version of Windows you're running. Check your computer's system information to see whether you need an x86 (32-bit) or an x64 (64-bit) version of the program, and then contact the software publisher."
I've tried running the program in question (Castle of the Winds) in every compatibility mode that is on the list and all it does is give me that error message every time. Other people have managed to get the program working, so I know it does work on Windows 7, but I can't see to get it to work for me.