Newsletter Mailer Log Cleanup error

Hi,

I am receiving errors from the Newsletter log cleanup.

The server cannot be upgraded for now, and I need to use CMSB v3.61.

The Newsletter Builder is v3.06.

Activity: Newsletter Mailer Log Cleanup

Summary: Error

Completed: 0

Function: nlb_mailer_log_cleanup

Output:
MySQL Error: Unknown column 'function' in 'where clause' in /home/xxx.com/public_html/cmsb/plugins/newsletterBuilder3_06/newsletterBuilder.php on line 550

Above refers to this part on the newsletterBuilder.php, but it seem like it is not different from the other older versions or the newest version.

// erase successful log messages with no output that are 10 minutes old or more
function nlb_mailer_log_cleanup() {

$deleteWhere = "`function` IN('nlb_mailer','nlb_mailer_log_cleanup') AND `output` = '' AND `completed` = 1 AND `createdDate` <= (NOW() - INTERVAL 10 MINUTE)";
mysql_delete('_cron_log', null, $deleteWhere);

}

What can I do to fix the error?

Thank you in advance.

Hiroko