Autoload database to libraries error

Hello everyone

I'm trying to configure libraries in autoload.php with:

$autoload['libraries'] = array('database', 'session');

but I keep getting this error:


A Database Error Occurred

Unable to connect to your database server using the provided settings.

Filename: C:\wamp\www\ci_series\system\database\DB_driver.php

Line Number: 125


When I remove 'database' from the array it works and I get the CodeIgniter welcome page.

How do I fix this?

Thanks in advance!!