Other than saying you should probably turn off any antivirus-related software, there's not much to say. We are not really officially supporting Windows 8 right now, but in general, anything that runs under Windows 7 shouldn't have any problems in Windows 8.
Under Windows 7, Microsoft own antivirus, which is what I use, doesn't complain with any of our installers, so I don't see why it should be any different under Windows 8.
Are you *sure* the problem is related to the antivirus, and it's not just an simple generic failed download ?
