Attached is a version which works with the B&N website after its revamp. As I mentioned above there is a few things broken on their website that I am not sure if/when they will fix so I want to give it a little more time before I officially release this.
From my quick testing, I "think" the plugin is fully working. There are some changes forced by their website changes. For instance B&N now only publish ratings in the web page rounded to a half star based system, rather than a numerical value like they had previously.
Also I am completely unable to get ratings for textbooks (fiction books are fine). Ratings on textbooks are rendered dynamically using javascript to allow hovering to change the rating etc. If someone fancies themselves a challenge then by all means please tell me where I can scrape the "starting value" from in the page as I lost the will to live rather quickly. I am sure others would be grateful if you can figure it out 
As an example, go to this url:
http://www.barnesandnoble.com/w/c-pr...han/1000055175
You can see it has a 4.5 star rating on the right-side - as for how it gets that value I welcome the answer.
Regardless, a version for you to test is attached to this post, let me know of any issues before I officially release it.