"Install.exe is not a valid win32 application" or “Setup.exe is not a valid win32 application"

This error appears when you attempt to install a program designed to run on older versions of Windows on the new 64-bit version of the operating system.

Solution: You won’t be able to install or run 16-bit applications on the new 64-bit version of WinXP. The solution is to obtain a 32-bit or 64-bit version of the program you are trying to install. In some cases you can obtain a 32-bit installer for the application and then still run the older application, even in 16-bit mode.

Ref: PC Errors