Urgent: Registration form errors

concrete5.6.4.0 php7.03

The following errors are thrown up when users try to register:

Warning: vsprintf(): Too few arguments in /var/www/vhosts/klc.co.nz/httpdocs/concrete/startup/localization.php on line 27

Warning: Cannot modify header information - headers already sent by (output started at /var/www/vhosts/klc.co.nz/httpdocs/concrete/startup/localization.php:27) in /var/www/vhosts/klc.co.nz/httpdocs/concrete/core/libraries/controller.php on line 421

any advice for resolution pls?