Nook download

Imhaving problem downloading books to my nook. When I download the book it appears to be working however when i try to pull book up on my nook it says that the book has been returned even though i havent read. When I try to redownload it says that the book is already downloaded and gives me option to replace or duplicate.  I have tried both andit looks as though it is doing partial download but when i try to pull up on nook it tells me book returned.  The system worked much bwetter when the books were downloaded to overdrive.