Fatal error: session_start

When I go on the site every now and reloading the page comes out this error:

Fatal error: session_start() [<a href='function.session-start'>function.session-start</a>]: Failed to initialize storage module: user (path: /home/web/www.animep2p.net/www/temp/sessions) in /home/web/www.animep2p.net/www/functions/session.php on line 178

How can we resolve???

http://diferior.com/forum/thread/development/bugs/from-time-to-time-i-get-this/page1.html