erro em session

Olá pessoal, alguém pode me dizer que erro é esse?

Warning: session_start() [function.session-start]: open(/tmp/sess_ec9b389cdab0f6ef7c0dfaece6bf4b7f, O_RDWR) failed: Permission denied (13) in /home/localhost/public_html/cod_top.php on line 2Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /home/localhost/public_html/cod_top.php:2) in /home/localhost/public_html/cod_top.php on line 2Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/localhost/public_html/cod_top.php:2) in /home/localhost/public_html/cod_top.php on line 2

Codigo na pagina cod_top.php

session_start("teste3");if(!(session_is_registered("login") AND session_is_registered("senha"))) {$LOgAdO = "no";}