I did some looking around on the Wayback Machine, and I found some interesting pages that were saved which -- although none of them have an even partially complete version -- were the pages for each of the three versions after the original. Since they haven't been posted on this forum yet, I thought I might share them.
When looking at the page for Hot Shot Business 2 (version 2 with four businesses), the one that was already posted here, I found that only the Pet Shop actually loads into the game. The other three do not, as they keep 'downloading files' perpetually. The .swf for this is at this link:
Hot Shot Business 3 (version 3) is also present on the Wayback Machine. None of the businesses are playable, but it does load into the menu which includes the chocolate factory. I found it here:
I had never played an online version of the game, but sure enough I found links for Hot Shot Business 4 (version 4) which might be the multiplayer game referred to earlier in this thread. This one includes the sixth business, Gateway Travel, but none of them worked in my testing.. The actual game appears to have the same issue as HSB3, where it will only go so far as to allow you to pick the business; after that, it goes to a tan screen that doesn't seem to progress. If you want, you can find it here:
Most of the buttons on each page appear to work, at least so long as you are able to play flash objects.
Since it appears that nobody can find any of the game files on the internet, should we start contacting members of the development team? Has anyone already contacted members of the team? I was able to find a few people related to the team that I was planning on starting with, but I wanted to make sure nobody has contacted them previously. It seems like a long shot, but it may be the only option left for us to have a chance at preserving the later versions (HSB4 is probably permanently gone).
Edit: By the way, there is still a way to play Flash objects in a browser. I followed this guide, which helps you to download the Pale Moon browser (one that allows you to use Flash without issue) and how to install the latest usable version of Flash (and to uninstall the versions that have a forced lockout, if you downloaded them).