When I try to download an aircraft, here is what shows up C:\users\AL\AppData\Local\fsstup-218-b6.zip is not a valid Win32 application. This is a sample of the response.
That's likely a problem with WinZip. Please try opening the ZIP archive with the default Windows browser/file manager. I'm not sure why people are still using WinZip - ZIP archive opening/creation has been part of the main OS since XP.