Beck, If the photos are not appearing in Preview when you select Books > Modified Register > Descendancy, check to see if you have a checkmark by Include Photos. If the checkmark is there, the photos should be shown in the book. It works fine in my PAF database.
When you try printing using PrimoPDF as the "printer", what happens?
It is possible that your PAF software has been corrupted and may need to be removed (Control Panel > Add and Remove Programs) and then installed again. Before doing so, I would make a backup with a new name and store it somewhere safe. (This may be unnecessary, but I would still do it. If you need to restore it later, it will need to be restored to the same location as the current database or the multimedia links may not work.)