If, as a course creator, I backup a course and restore it on to an existing course, deleting it first, my role as 'teacher' is lost by the end of the restore and an error is thrown. When I re-login the course is restored on to the other course as requested, and only problem is that I am no longer teacher of the course.

As an aside I would prefer if teachers could do this without being course creators as I do not wish them to create new courses, but I do with them to be able to copy their courses on to their next year occurrence! I hope this will be possible in Moodle1.7 with the new focus on roles.