More than likely your browser is simply installing the same cached download, over and over again. Did you try clearing the browser cache?
Removing Norton is a pain, due to the damage it does to system files when it installs.
Try downloading a different version of the game (AH2322.EXE, AH2321.EXE, or AH2320.EXE).
If you get that message with all three, then something is still corrupting the download. As the file is downloaded using TCPO, it should be fine as TCP includes checks for data corruption. This implies the file corruption is coming from the attempt to run it.
Are you trying to run it from a hard drive or an SSD? Are you running RAID?