Well, it seems we're disregarding the actual story in lieu of bitching about textbooks. So here's my story of interest:
My own stupid textbook story is from Statics. The prof listed a textbook, title, version and ISBN. I ordered online to save some cash, everyone else bought from the campus bookstore.
About two weeks in, I've failed every homework problem. Turns out the version that was listed, and the version I had bought, was the METRIC version, while the campus bookstore had ordered the IMPERIAL version, which everyone else, including the professor, had (I checked the ISBNs, mine was right, so either they have two versions under the same number, or the bookstore "corrected" it to the imperial version). The problems were the same, save for the units.
Brief aside: Why the hell is there even an engineering textbook in non-metric units? Who the hell is designing bridges in feet, pounds and slugs? It's probably just to keep American students from buying cheaper foreign copies.
In any case, we worked out a deal - I just copied the text of the problem before showing my work. My grade instantly shot up. Not quite to an A- despite having passed an "Algebra and Trigonometry" class, I'd never actually been taught trig, and was trying to learn it independently for both Statics and Calc II.