Dragan,
About two years ago I had a very similar problem which took may (grey) hair out.
You decribe exactly the same sequence, and had to do with the COMCTL32; Now look at a similar thing happening on setup-errors (look at the threads a little higher), also noticable on other forums; I talked to MS about this, who admitted that "timebombs can be there" but didn't recognize my problem (so, similar to yours, if not exactly the same);

One by one PC's start falling over, even PC's at home never used, and worse, the PC's at customers. My priceless solution back then :

Create the smallest distribution set you can imagine, put the expected problem-maker in there (for me this was COMCTL32) and run this setup on the concerning PC (if I'm right, in the end all of them). And now all works fine.
Note that two years ago I did all there was to do (admitting OCXes to the registry explicitly in many ways etc. etc. Nothing helped.
The setup luckily did ...

Now hope it helps for you too.

Note : If it is really the same problem you should be able to notice it by starting VFP.EXE, create a Form and drag an OCX-object onto it. In my situation even that didn't work anymore (and did for years, and should of course).

Once you find the solution, please let me (us) know; I'm shivering already.