Error message

• Warning: Cannot modify header information - headers already sent by (output started at /home/webserver/www/htdocs/neuro/includes/common.inc:2820) in drupal_send_headers() (line 1501 of /home/webserver/www/htdocs/neuro/includes/bootstrap.inc).
• Error: Call to undefined function each() in SMTP->Data() (line 393 of /home/webserver/www/htdocs/neuro/sites/all/modules/smtp/smtp.transport.inc).