You must first make sure you have installed the extensions by going into your cPanel and clicking 'Install FrontPage Extensions' on the desired domain or subdomain.
If your DNS is still propagating, FrontPage extensions can work. You must replace http://domain.com with http://serverip (where serverip is the IP address of your website).
If you ever connect to your site with FTP, it will corrupt the FrontPage extensions for that site. You will need to go into your cPanel, click 'Uninstall FrontPage Extensions' and reinstall them before you can use http publishing, again.
Subdomain and Addon domains advice.
In order to install FrontPage extensions on any sub-domain or addon domain, you need to install the extensions on the primary domain name, first.
If you are having issues with installing the extensions, you should remove all FrontPage extensions and then clean up old extensions on all domains it was installed on. Next, install front page extensions on the primary domain name, and then install them on all the sub-domains or addon domains you want. At this time there is really no way to have FrontPage extensions just installed on sub-domains or addon domains without them first being installed on the primary domain name.