I don't have the book in my library. I'm not sure if you should be concerned or not. It could just be a flub in your account...B&N may have added it by accident. Perhaps a B&N mod could answer that question.
I've seen a few other people report this.
It happened to me and I assumed it's b&N's way of promoting some titles.
However, the suggestion that it's an error seems more likely.