what type of data do you use? I've seen page selector links that had the 'selected page' removed so it can't resolve the url in the textbox. But in the database it store's the exact path, so it still show's data in your repeaters.
Could be that the controls you picked can't resolve anymore due to a change in type/guid/id/path/etc..
Clear caching might also resolve the issue, but you might have tried that already.