iweb publishing to wrong domain name (domainname.com/domainname.com as opposed to just domainname.com)

The first part is your domainname.

The second part is your Sitename.

You typed the characters yourself.

If you do not like them, use other characters.

Here's a text from another post :

iWeb does nor create different URLs. iWeb creates a folder with the Sitename and the pages within it.

Nothing exotic.

I think it's very convenient, since it allows me to organize my pages based on subject, topic or whatever I choose. I've been doing that for the past 16 years.

Anyway, read this :

The concept of iWeb Sites

To avoid the Sitename in the URL, read my solution. It's very technical but in the end it saves time. And best of all, iWeb is not involved :

Avoiding the iWeb Sitename in the URL

An easier, time-wasting, solution is to publish to a folder on your desktop.

Open that folder and move the content of that folder to the root of the webserver with a FTP application.

Everytime you make changes to a page, you have to repeat these steps.

But the result is what you want.

And here's a re-post with some additional info about using an index.php file :

Avoiding the iWeb Sitename in the URL

Works on all servers. With or without a subdomain I may add. Like this one :

http://wyodor.byethost8.com/htdocs/index.html

Not as easy as publishing to a folder, but in the end it save time.

See this post that explained the link above :

Re: iWeb keeps populating a site name at the end of my url. Causing error.

So you see it is not something that is broken that needs to be fixed. It is often discussed in this forum.