I would suggest downloading another reader app like Moon Reader and see if your book works with that. If not, then you would have to contact BN customer support.
Here are my overdosed-on-films reactions: (1) You
don't need no stinkin' badges - er - additional reading app.
Leave the additional app; take the cannoli - er - faulty book, to BN Customer Support.
I had this problem once with a book and I don't remember how I fixed. I may have changed the background color in the reader.