SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6 pl2): Invalid SQL: UPDATE bb1_guthaben_bank SET akt_jahr='2021', crashtag='124', boersencrash='0',boersencrashdate = '', boersencrashaktienwert='', boersencrashprozent='',boersencrashaktienwertneu='' WHERE bankid='1'
mysql error: Incorrect integer value: '' for column `admin_galaxy_1`.`bb1_guthaben_bank`.`boersencrashaktienwert` at row 1
mysql error number: 1366
mysql version: 10.2.40-MariaDB
php version: 5.3.29
Date: 26.09.2021 @ 18:51
Script: /wbb2/register.php?sid=c6211e6531f13a829f72aef1ae668096
Referer: