As .exe files without any reliance on remote content, yes I would agree, the problems are likely the individual computers.
First, perhaps ask those users to try a different machine if they can, just to verify they can get it working elsewhere....as opposed to perhaps the distributed file being corrupted for those few users somehow.
To troubleshoot on the specific machines, that can get very complicated. Three easy/common issues:
1. video card drivers - ask them to find the latest version and update. It's a pretty generic solution but can be the root of many problems
2. Install the latest Flash player (though your .exe may include the player, perhaps its conflicting with one they have installed?)
3. Ensure they have no viruses on their machine. If they do, absolutely no guarantee the product will ever work for them. Getting them to admit they have one, or even discovering they have a virus, may be impossible though. Do they at least have current antivirus software running?
3b (and if they do have AV software running, see if they can disable it temporarily and successfully run the program. Like the video card driver issue, while unlikely, it could be their AV software is interfering with the .exe playback)
HTH
Erik
