Mensaje de error

Warning: Cannot modify header information - headers already sent by (output started at /home/wmentrelasartes/public_html/lab2015/index.php:11) in drupal_send_headers() (line 1237 of /home/wmentrelasartes/public_html/lab2015/includes/bootstrap.inc).
Warning: Cannot modify header information - headers already sent by (output started at /home/wmentrelasartes/public_html/lab2015/index.php:11) in drupal_send_headers() (line 1237 of /home/wmentrelasartes/public_html/lab2015/includes/bootstrap.inc).
Warning: Cannot modify header information - headers already sent by (output started at /home/wmentrelasartes/public_html/lab2015/index.php:11) in drupal_send_headers() (line 1237 of /home/wmentrelasartes/public_html/lab2015/includes/bootstrap.inc).
Warning: Cannot modify header information - headers already sent by (output started at /home/wmentrelasartes/public_html/lab2015/index.php:11) in drupal_send_headers() (line 1237 of /home/wmentrelasartes/public_html/lab2015/includes/bootstrap.inc).
Warning: Cannot modify header information - headers already sent by (output started at /home/wmentrelasartes/public_html/lab2015/index.php:11) in drupal_send_headers() (line 1237 of /home/wmentrelasartes/public_html/lab2015/includes/bootstrap.inc).
Warning: Cannot modify header information - headers already sent by (output started at /home/wmentrelasartes/public_html/lab2015/index.php:11) in drupal_send_headers() (line 1237 of /home/wmentrelasartes/public_html/lab2015/includes/bootstrap.inc).