I am able to open the book on my computer. I can not send it to my Nook from the ADE. I get a message that says there is no authorization to copy the book.

I borrowed an ebook from the library and downloaded it to the ADE I recently put on my computer. I can open the book and read it on my computer. When I try to send the book to my Nook I get a message saying that there it is not authorized to copy the book. What can I do to correct this problem?

I have used the ADE without problem on my old computer. So this is new for me.