Warning:  [mysql error 1048] Column 'object_id' cannot be null

INSERT  INTO `piwigo_activity`
  (`object`,`object_id`,`action`,`performed_by`,`session_idx`,`ip_address`,`details`,`user_agent`)
  VALUES('user',NULL,'logout',NULL,'1ca009ea1a92885b25e70ce5613ade84','216.73.216.145','a:1:{s:6:\"script\";s:5:\"index\";}',NULL) in /www/htdocs/w0183c2c/lightbox.andreasgregor.photo/include/dblayer/functions_mysqli.inc.php on line 847