[KDP Print Previewer keeps showing errors when there aren't any]

I was getting almost the same "issues," though my book is a novel, so no pictures or text boxes. It was showing about twenty pages with characters outside the print area, though these characters did not show up on the PDF file. It had said something about embedding fonts so I went back to my Word file and embedded the font. This was a somewhat complicated process by itself. I then converted it to PDF, uploaded, and the problem was solved. While this isn't the exact problem the OP had, others might find this thread, as I did in a search on my issues, and find it helpful.