thanks very much for sending me your backup file. As you say, it restores the course without errors, but without any activities.
The reason that no activities are restored is that no activities were backed up from the original course. The backup file contains all the user information, and I can see all the HotPot files in the course folder, but there are no HotPot activities defined in the course. If fact, there are no activities of any kind. It looks like you backed up the course WITHOUT any activities
Another thing I noticed was that the original course was on a Moodle 1.7 site. Moodle 1.7 is not a stable version yet, so it could be that backup was not fully functional on the your Moodle 1.7 site when you made the backup.
It looks like you have to either redo the backup (I notice the original site is still active) or re-add the activities into the empty course you have already restored.
best regards
Gordon