Permision does not transfer to Nook first version

I can successfully download an Epub from my local lending using My Media Mall. I am able to open the book and read it on my PC. When I drag the book over to the Nook icon, the book is successfully copied to the Nook and the Nook even shows the book's cover and expiration date. When I go to open the book on the Nook, I get a message the book has already been returned. I reloaded the E book for a second time and received the same error after dragging the file to the Nook Icon.