and enter 5250 in the Search Support box on that page. I think you did most of those steps. But what concerns me it the fact that you are continually seeing the "permission" message.
The first piece of that article to check, is the corrupt User Account. Yes, I did see that you addressed that, but please try the steps in this article.
If that doesn't work, then please use the Control Panel (Start menu) and Delete Family Tree Maker completely, then try to install again.
Use the normal Install, (Run As Administrator on the setup program) first. If that doesn't work, then the other installation that is talked about in that article.
There may be something else going on, on your PC, but please give this a try first.
Just thought of one other item, has this PC had Family Tree Maker on it before? That really should not make any difference, as most of my Desktop PCs have had at least 3 versions of the program on them. (over the years).
The other question: Have you had any other installation of program issues on that PC?