You receive this error because the application is not compatible with your Windows Vista computer. Video Screensaver has been developed to run only on Windows XP, Windows ME, Windows NT 3.x, Windows NT and Windows 98 operating systems. You can try running the software using 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 a compatible operating system from the drop-down list. Click Apply and then OK.