رسالة الخطأ

• Warning :Cannot modify header information - headers already sent by (output started at /home/demo4dev/public_html/includes/common.inc:2806) في drupal_send_headers() (السطر 1501 من /home/demo4dev/public_html/includes/bootstrap.inc).
• Error :Class 'Drupal\form_builder\FormBase' not found في form_builder_cron() (السطر 360 من /home/demo4dev/public_html/sites/all/modules/form_builder/form_builder.module).