Error message

• Warning: ini_set() [function.ini-set]: Headers already sent. You cannot change the session module's ini settings at this time in include_once() (line 271 of /var/www/teaterseachange.dk/rehearsalmatters.org/sites/default/settings.php).
• Warning: ini_set() [function.ini-set]: Headers already sent. You cannot change the session module's ini settings at this time in include_once() (line 272 of /var/www/teaterseachange.dk/rehearsalmatters.org/sites/default/settings.php).
• Warning: ini_set() [function.ini-set]: Headers already sent. You cannot change the session module's ini settings at this time in include_once() (line 280 of /var/www/teaterseachange.dk/rehearsalmatters.org/sites/default/settings.php).
• Warning: ini_set() [function.ini-set]: Headers already sent. You cannot change the session module's ini settings at this time in include_once() (line 287 of /var/www/teaterseachange.dk/rehearsalmatters.org/sites/default/settings.php).
• Warning: ini_set() [function.ini-set]: Headers already sent. You cannot change the session module's ini settings at this time in drupal_settings_initialize() (line 819 of /var/www/teaterseachange.dk/rehearsalmatters.org/includes/bootstrap.inc).
• Warning: session_name() [function.session-name]: Cannot change session name when headers already sent in drupal_settings_initialize() (line 831 of /var/www/teaterseachange.dk/rehearsalmatters.org/includes/bootstrap.inc).