Trying to add borrowed books to Nook and computer keeps saying, "Cannot authorize books to copy"

[katepani]

I downloaded Adobe Digital Editions to my computer and borrowed some books from the local library. I'm trying to copy the books to my Nook to read but I keep getting the message: "C_E COPY_NOT_ALLOWED- no permission to copy the book."  I had no problem on my previous computer with doing this. Please help!