Are you trying to run the Setup.exe file for 64 bit Windows 7 from within a current 32 bit operating system?
The system message "setup.exe is not a valid win32 app" seems to imply exactly that, but I am not sure. I thought that I had a 64bit operating system based on the processor listed in "system properties" - it had the processor as AMD Athlon 64 processor. Is there any other way to determine whether I have a 32bit or 64bit operating system? - thanks.