Unfortunately, you received this error because Prince of Persia: The Two Thrones is developed to run only on Windows XP and Windows 2000 platforms. However, I suggest you try the Compatibility Mode. Right click on the program icon and go to Properties > Compatibility tab. Check the Run this program in compatibility mode for box and select Windows XP or Windows 2000 from the drop-down list. Click Apply and then OK. Also, you can try to install the game in Windows XP Mode environment. Windows XP Mode is a free utility developed by Microsoft that allows you to run applications compatible with Windows XP directly on a Windows 7 computer.