Can nor add journal article

Can not add journal article

When try to add journal article, the error message raise :

PDOException: SQLSTATE[23502]: Not null violation: 7 ERROR: null value in column "cid" violates not-null constraint: INSERT INTO biblio_contributor_data (name, lastname, firstname, prefix, suffix, initials, md5) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6); Array ( ) in drupal_write_record() (line 6975 of /home/wa2n/web/drupal-7.12/includes/common.inc).