Concerning the 404, perhaps you have to check if you correctly setup your domain or subdomain in you cPanel or other administration tool. Perhaps you could use the hello world procedure in tutorial video 7 to check the server setting.
If you have a .htaccess present, perhaps there is a "rewritebase" active with a wrong value.
If you want that we setup your environment, this is also possible with our billable support that you can order at
www.jms2win.com/en/joomla-multisite?page...35&category_id=1