Strange Problem with PHP sessions path !!!

[lyndros]

Hello guys im having some troubles on a site that is currently working when i make phpscript to start a session then that error appears

Warning: session_start() [function.session-start]: open(/var/www/web5/phptmp//sess_xxxxxxx, O_RDWR) failed: Permission denied (13) in /var/www/web5/web/final/login.php on line 2

the code is right as u can see here the problem is the path, because it adds an extra bar, i took a look in my vhost for the site and the path it's just the same than other site where the script is working fine....

how can i solve this?

thk u in advance :-P