No matter where you get the audiobook download from, make sure you transfer the book in MTP mode so the license gets transferred. Rhapsody isn’t the only place subscriptions are used, most audiobook downloads have subscriptions too.
Based on your comment about “6 parts” I’m guessing the book is from OverDrive. OverDrive audiobooks use their own software to transfer to the Clip. After you click the Transfer button a window will pop up and either the 1st or 2nd screen gives you an Advanced button. Click Advanced and change the directory Music to Audiobooks (note there is an ‘s’ making audiobook plural) so that you can take advantage of bookmarking where you’re at if you go off to listen to music (assuming you have 01.01.29 or 01.01.30 firmware).
If you’re lucky enough to have access to NetLibrary audiobook downloads too, NetLibrary works well using Windows Media Player. Two notes: (1) play the file in WMP first and it will download the license. (2) then you’ll want to right click the audiobook in the right pane (should be Now Playing List), select Advanced Tag Editor, and change the Genre to Audiobook (note there is not an ‘s’ here) so that you can take advantage of bookmarking where you’re at if you go off to listen to music (again assuming you have 01.01.29 or 01.01.30 firmware). Then add the audiobook to the Sync tab and sync to the Clip.
Let us know how things work out. Hope this helps.