Can't Run SETUP.EXE file

I'm attempting to install an A920 printer and downloaded and installed the software with no apparent problems. But when I clicked on the SETUP.EXE file to complete the installation, a window popped up saying: "C:\Windows\SYSTEM32\AUTOEXEC.NT. The system file is not suitable for running MS-DOS Microsoft Windows Applications. Choose close to terminate application."

I am operating on Windows XP and have gone to the support center's trouble shooting page, everything points back to that error window that I have no idea how to solve.

any help is much appreciated.
thanks,