You don't say whether you are on a Linux or Windows server. But on Linux servers and probably Windows servers also you can use the LunarPages control panel to install the FrontPage server extensions on your own. If the extensions are installed publish to
http://domainname.com like you are.
If you do not use the FrontPage features that require the extensions, you can publish using FTP publishing, however in that case I still prefer the HTTP publishing over FTP.
You can tell if the extensions are installed and working by browsing to your home page, selecting the Internet Explorer File menu and choosing Edit With FrontPage. If the extensions are installed and working you will be presented with a username/password prompt. If the page opens in FrontPage without a password prompt, the extensions are not working.