Network created and subdomains are producing 404 error page - not found

Hi. This is probably not related to the theme but I happen to be using magazine. I have been through the steps very carefully and created a multisite/network install from a simple wordpress installation. I have a network admin back end, the problem is that when I try to visit a subdomain site it takes me to the host's placeholder page and when I try visit a sub-site's dashboard I get the following 404 error:

The server can not find the requested page: (port 80)

site is

Can you explain why the multisite install has not worked yet?