I have just had similar problems, but I don't know if this will be of any help.

I am using several Active-X components from dbi-tech. My problem was that I had several different versions installed on my computer (I started with a demo and bought the products later). When I bring up the property page for the control and look at the About-page to see which version I am using, it always shows the latest version number, even if the actual component I am working with is an older version. For example I had a class with the version 1.0 of the component, but the About-page always showed version 3.5. (I don't know if this is a bug or if it is supposed to be like this.) At the beginning I wasn't aware of this, and I couldn't figure out the problem with registering the component. The problem of course only showed up on other computers, not mine since I had both versions registered. The only place I could find information about the version I was actually using was in the OleClass property. This showed something like ctDEDIT.ctdEDitCtrl.1, where the number indicated the version. I had to rebuild my classes, making sure I was actually subclassing the right version of the ocx file. Sometimes vendors compile different versions of the same component with different Class Ids, so that different versions can coexist on the same computer

You could also open the form or the class causing the problem as a table and go to record no 15 and find out which object is actually causing the problem, but I guess you are aware of this.