It took forever—two and a half months—but the Barns and Noble Nook team finally got what-ever-it-was straightened out. Gladiator Girl went on sale in the Nook store last week. However, because I didn't have access to update the book file durning the delay, the version they had was out dated. The latest version fixes several small proofreading errors, and makes one significant change in the manuscript: The first two sentences of the book have been switched around.
I updated the file last week, and as of today, this evening, the latest version is the one available. Nook owners, and Kindle owners will both be buying the same updated version. Although the Google ebook store has the new version, they have yet to update their store listing.