Fehlermeldung

• Warning: Cannot modify header information - headers already sent by (output started at /var/www/union-gampern.at/html/includes/common.inc:2800) in drupal_send_headers() (Zeile 1501 von /var/www/union-gampern.at/html/includes/bootstrap.inc).
• Error: Call to undefined method BirthdaysBirthday::isLeapYear() in _birthdays_get() (Zeile 614 von /var/www/union-gampern.at/html/sites/all/modules/birthdays/birthdays.module).