You must first make sure you have installed the extensions from going into your cpanel and clicking 'Install FrontPage Extensions' on the domain or subdomain you want them on.
If your DNS is still propagating, FrontPage extensions will not work. Your only option would be to upload your site using FTP during this time.
If you have ever connected with FTP, it will corrupt your frontpage extensions. You will need to go into your cPanel, click 'Uninstall FrontPage Extensions' and reinstall them.