kdavi172,
I am facing the same problem with an excel document that has many pictures included.
After many google searches I came across a solution:
Not sure what version of windows etc, that the pdf is referencing, but my registry layout looked slightly different.
I added the one key to the registry, with a value of 1 more zero that what is shown in the linked pdf and now my excel sheet is not a black box when re-opened.
this is the registry key that I added.
What I did notice after the fix that my Catia drawing file size was now very large.
The fix for this was to go back into my excel and format/compress the pictures.
If I would have done that first, I probably would have never had the black box problem.
I assume that this will fix your PDF problem, but you may have the same problem with a very large .CATDrawing.
You may want to get your I.T. involved for editing your registry if you are unfamiliar.