Error when session table is updated

[eluser]LuckyFella73[/eluser]
Hi,

I get the following error message when I try to load a page:

Code:

Error Number: 1064

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '`< 1340198948`' at line 2

DELETE FROM `jaz_sessions` WHERE `last_activity` `< 1340198948`

Filename: D:\xampp\htdocs\journaldujazz\system\database\DB_driver.php

Line Number: 330

When I refresh the page the message is gone. I autoload the session class btw.
It's my first project using CI 2.1.1 (I did the upgrade from 2.1 to 2.1.1,
overwriting system folder and index.php on root)

Does anyone know what may cause that error message?