Fehlermeldung

• Warning: Cannot modify header information - headers already sent by (output started at /var/kunden/htdocs/selbst/c2os/includes/common.inc:2861) in drupal_send_headers() (Zeile 1554 von includes/bootstrap.inc).
• Error: Class 'DOMDocument' not found in filter_dom_load() (Zeile 1107 von modules/filter/filter.module).