Error (2): session_start() [<a href='function.session-start'>function.session-start</a>]:
open(/var/php_sessions/sess_719f00060e4f4e2d3b96b4fa0b1b428b, O_RDWR) failed:
No such file or directory (2)
file:/folder/folder/b1216/folder/test/includes/contact_us-lib.php
Error (2): session_start() [<a href='function.session-start'>function.session-start</a>]: open(/tmp/sess_9bde038ce1518c5ea932e1d670c5b6c3, O_RDWR) failed: Permission denied (13)
Sessions are used to keep track of the user accessing the form page.
While configuring PHP, the session needs to be configured on the web server.
On your web server, PHP session is not configured properly. So when the script tries to create a session, PHP throws this error.
Request your web hosting service provider/server admin to configure PHP session on your web server. Quote the error message you received.
If you run your own web server, then you have to update the php.ini under the [Session] section. make sure that the session.save_path is configured to an existing folder and that the folder is writeable.