Problem with subdomain install in multisite?

Hello,

I am trying to bring all my websites under a multisite installation. I installed the multisite with softocolous. I changed the part in wpconfig as follows.

/* Multisite */
define('WP_ALLOW_MULTISITE', true);
define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', true);

Still when I create a subdomain multisite, I get the Server not Found page.

What is missing in my installation?

Thanks