Welcome to MY WORLD! I've been beating on this issue (politely, I hope) for over a year.
You are totally out of luck if you get hung up for any reason and have not manually SAVED at some point(s). You will lose everything (including art), and will have to start over.
I feel for you. I try to at least remember to manually Save after ever couple of CD's. But I still get "caught" (it happened just a couple of days ago). It's maddening, because it seems like there should be a simple solution. Plus, by having to save manually, it RE-saves the CD's you've saved to that point, which can make it take a bit of time to save a large number of CD's. Programmed correctly, it could auto-save (either as a feature or as an option for those who don't want to bother...) incrementally, so it wouldn't take so long.
At least now I know I'm not alone with this issue. Maybe if more people speak up we'll be heard. Otherwise, ABB is a great program that I could not do without! And even without an Auto-Save function, I would never give it up....what was it Charlton Heston said? "They'll have to pry it out of my cold, dead hands!"
I also highly recommend Delicious Library, for keeping track of your audiobooks. It's very cool and Mac-like in design.