The impression I've gotten from all their presentations about MinWin and Metro is that Metro and Win32 are independent subsystems and that the Win32 subsystem is not being ported/supported on ARM thus no Win32 applications will run on the ARM based Win8 systems. I can't find where I read it but I remember seeing something about the Win32 subsystem possibly not even being installed by default on systems and only being installed if you tried to install a Win32 app.
"Furthermore, applications for the ARM version of Windows 8 will only be available through the "Windows Store" - and only apps compiled to use its "Metro" touch interface will appear there."