ADE & nook

I am using ADE 4.5 to move ebooks from overdrive to my Nook.  today, ADE seems to get the book from overdrive and then transfer to my nook.  when i try to open the book on the nook i get an error msg. 'this book has been returned.loan not on record.'  I go back to ADE and the book is still there. I try to transfer to the nook and ADE tells me that the file already exists.  This happens with four titles that ive tried.