We are unable to edit any cck fields because we keep receiving this error:
Invalid argument supplied for foreach() in /home/drupal_6x_prd_01/sites/all/modules/filefield/filefield_widget.inc on line 512.
It doesn't matter what field we're editing, if we select the fields to edit, and then submit them - the module reports that the processing was completed without any problems. But when we look into the logs, we see that error. It seems to prevent the actual processing to fire.
This is an issue linked to http://drupal.org/node/358617.