Error message

• Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/includes/bootstrap.inc:1717) in drupal_send_headers() (line 1576 of /var/www/html/includes/bootstrap.inc).
• Error: Call to undefined function dsm() in bridge_assessment_cron() (line 494 of /var/www/html/sites/all/modules/custom/bridge_assessment/bridge_assessment.module).