Hi, Peter - maybe you're logged into an Address Book. You can't Backup or Restore when logged into an Address Book.
What you have to do is open Administrator but when it prompts you for a login click "Cancel" -it will then present you with a list of Address Books, and you click "Cancel" again. At that point you're in Administrator and you can select Utilities - Backup and Restore. When you do, it will prompt you for an Address Book and at that point you will log in.
Confusing, but if that was your issue this is the way around it. It does work.
- R.