sesiuni in php

de cand am instalat wamp, cu functia session_start() sant probleme. In php.ini am setat corect, ce altceva mai poate fi?? asta este eroarea ce apare:Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at C:\wamp\www\guestbook\mesaj.php:8) in C:\wamp\www\guestbook\config.php on line 2iata eroarea, mai exact:Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at C:\wamp\www\guestbook\mesaj.php:8) in C:\wamp\www\guestbook\config.php on line 2Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at C:\wamp\www\guestbook\mesaj.php:8) in C:\wamp\www\guestbook\config.php on line 2