Warning: session_start() [function.session-start] error

Q: When Jigoshop is activated I get the error on Admin panel and site:

 Warning: session_start() [function.session-start]: open(/var/chroot/home/content/25/9042525/tmp/sess_liq96jf40gu1046t57nq8ecah2, O_RDWR) failed: No such file or directory (2) in /home/content/25/9042525/html/wp-content/plugins/jigoshop/classes/jigoshop_session.class.php on line 20

This message totally messes up all displaying. If I deactivate Jigoshop everything displays perfectly. I tried deleting Jigoshop and re-installing it but it didn’t help.

A: The session data indicates you need to contact your host.