As-tu bien renommé config.php.new en config.php ?
Si oui, et comme tu n'as très certainement qu'un seul serveur de base de données, tu n'as besoin de remplir que :
PHP Code:
// ****** DATABASE NAME ******
// This is the name of the database where your vBulletin will be located.
// This must be created by your webhost.
$config['Database']['dbname'] = 'forum';
(...)
// ****** MASTER DATABASE SERVER NAME AND PORT ******
// This is the hostname or IP address and port of the database server.
// If you are unsure of what to put here, leave the default values.
$config['MasterServer']['servername'] = 'localhost';
$config['MasterServer']['port'] = 3306;
// ****** MASTER DATABASE USERNAME & PASSWORD ******
// This is the username and password you use to access MySQL.
// These must be obtained through your webhost.
$config['MasterServer']['username'] = 'root';
$config['MasterServer']['password'] = '';
La configuration du serveur Slave est à ignorer.
Et pour finir :
http://www.vbulletin.com/docs/html/ 