If you are using Lighttpd on CentOS and installed with command line (yum, rpm etc.), you can have this problem. I had this problem very much. Every fresh installation of lighttpd comes with this problem.  When you are installed php scripts which uses php sessions, it wont work and wont give an error.  Because lighttpd can’t write on php session folder.

CentOS comes with Apache for httpd when installed and configured all things for Apache including directory owners. There is a directory php writes session data, located at /var/lib/php and named session.

Here is the solution. Just give it all permissons. You can change the owner but Apache wont work.

Solution command:

chmod 0777 /var/lib/php/session -R