Share 'Saving fields fails: "Unknown property"'

I followed the Adding Visibility Options to Your Member Profile Pages tutorial exactly but submitting the form always fails due to an "Unknown property: profileVisibility" error. I double- and triple checked the code for any typos but I cannot find any. The form-data is submitted properly but calling "$user->save();" always breaks it. snippet from /widgets/index/models/user.php [code] ..... p…