Barbara,
I downloaded the Harvard Complete Classics and it shows up as a normal book. No issues. This may solve my problem. If I start reading those classics I may never need to download another book!
I think this tells me the issue is related to the images. I still have my Kindle Oasis. I tried to load the book from The Kindle to Calibre. I found the book file buried inside a couple of folders (I think it was .kfx). I loaded that file but still got errors. I did notice that there were a lot of other files on the kindle for this book compared to other books. So I am guessing that there is something different about Kindle books with extensive images. I wonder if there are any clues about these differences in these files that I can detect before I commit to purchasing the book on Amazon?
Thanks,
Joe