Is your website not showing up with a custom domain in iWeb?

You can find a solution here or just do this: “Move a page to the top of the site and then back again.

iWeb will create a new index.html file that redirects to your current site on the server.

Or rename your current Site > Site and publish.

Or publish your entire site again.

Everything is published in the iDisk > Web > Sites folder.”  Thanks Wyodor!