Audio book won't play - "Synchronize to confirm your music subscription"

I download audio books from my local library (part of Midwest Collaborative for Library Services) and transfer them to my Clip+ using overdrive software.  The first 2 parts (tracks) of each book play fine.  However, when going to the third track, I get the message “Synchronize to confirm your music subscription” and the third track (and later tracks) won’t play.