Gordon, after the update to Quizport for Moodle 1.9, backup and restore don't handle the quizports any longer. I don't see the quizports appearing in the list of things being backed up now, and they do not appear in the restored file.
Could a change in the update have caused this? I've been backing up and restoring quizports successfully up till I updated to the very latest QuizPort for 1.9 last night.
If you don't spot this on your server, I'll show you on mine.