Out of pure desperation (oh, well…) I tried to edit and save the settings for the automatic posting at delicious.com (as the service is now known as) without changing the actual settings, and that seems to have done the trick. Except that the posting is now made at a different time of the day.
But you can’t have it all, can you?
Update: As you can see in the comments, this solution hasn’t worked for everybody. Strange.