Can't login to Admin section.

Hi,

I was about to add more stock to my site but I came accross this error message :

Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /home/dragoni/public_html/biz/includes/classes/class.smtp.php:1069) in /home/dragoni/public_html/biz/includes/functions/sessions.php on line 84

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/dragoni/public_html/biz/includes/classes/class.smtp.php:1069) in /home/dragoni/public_html/biz/includes/functions/sessions.php on line 84

Warning: Cannot modify header information - headers already sent by (output started at /home/dragoni/public_html/biz/includes/classes/class.smtp.php:1069) in /home/dragoni/public_html/biz/admin/includes/init_includes/init_templates.php on line 36

Warning: Cannot modify header information - headers already sent by (output started at /home/dragoni/public_html/biz/includes/classes/class.smtp.php:1069) in /home/dragoni/public_html/biz/admin/includes/functions/general.php on line 21

What can I do to resolve this?

Thanks,

Alex
.