When i input the ISBN on this particular book, it shows as a paperback, but it's really a hardcover.

At the side, when it says 'Or choose an alternate edition below' and "Are you meaning to post one of these other book types"...

Should i post it as the Hardcover edition, even though the ISBN it shows for the Hardcover version is different? This book comes in three forms, two different paperbacks and one hardcover. I assume that changing it to the Hardcover is the correct option, but i don't want anyone to say later that this book wasn't the exact ISBN they asked for, either.

Thanks in advance.

The hardcover listing with a different ISBN must be a different edition.  When listing by ISBN gets you an incorrect/different binding type  the Help Center says to enter the book without an ISBN.  When you post it has to match all four criteria: Title, Author, ISBN and Binding Type.  Since the ISBN has been used for both binding types (and PBS only has room for one) you have to enter it as a non-ISBN book.  Just remember to include the book description from the back of the book, it will help the book move more quickly.  If you can find and upload a cover it would help even more.  Then you can advertise that you have this oddball edition in the Book Bazaar, and with any luck it'll move faster than if you didn't have the problem in the first place.  Hope that helps :)

You will have to post this book as if it didn't have an ISBN...posting it under the wrong ISBN but correct book type is not allowed as it posting it under the correct ISBN and wrong book type...ALL points have to match.

Thanks everyone! I appreciate the help! I wonder why they even give you the option of choosing an alternate edition... lol.

It gives that option because many people just search the book and click on it to post w/o matching the ISBN#.  They see the title or cover and assume it's the same book.  So that, hopefully, helps cut down incorrectly posted books.