Why query cache do not work?

"Configured database connection has cache enabled. Aborting."
This is my problem.

I use this guide http://www.codeigniter.com/user_guide/da...ching.html for set the query cache and this is my database.php

Code:

$active_group = 'default';
$query_builder = TRUE;

$db['default'] = array(
    'dsn'    => '',
    'hostname' => 'localhost',
    'username' => '',
    'password' => '',
    'database' => '',
    'port' => '3306',
    'dbdriver' => 'mysqli',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => FALSE,
    'cache_on' => TRUE,
    'cachedir' => 'application/cache/site',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => TRUE,
    'compress' => TRUE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => FALSE
);

The cache/site is writable...
I would not know what might depend.


Thanks for your reply