I just did a fresh install of WP 3.1.2 and followed the instructions to activate multisite. (Copied the .htaccess content, etc.)
I chose subdomain and my server's support team added wildcard DNS for my domain.
As the admin, I created a new user. (The intention was to create a default theme for use when users create a blog, using the "default theme" plugin.)
I then added a site for this user. No errors reported during this quick process.
I go to view the dashboard of this new blog, yet I receive a 404 error.
What am I missing?