CAN'T OPEN LIBRARY BOOKS TO ADE SO CAN DRAG TO NOOK

I HAVE A MAC PRO AND A NOOK GLOW LIGHT. AM ATHENICATED. DOWNLOADED ADE 4. SELECTED BOOK IN PUBLIC LIBRARY ACCOUNT AND DOWNLOADED. WHEN TRY TO OPEN FROM DOWNLOADS TO ADE GET MESSAGE: "UNABLE TO DOWNLOAD. ERROR GETTING LICENSE. LICENSE SERVER COMMUNICATION PROBLEM: E_ACT_NOT_READY." WHAT AM I DOING WRONG? RICK