Yes, this is because Apple changed the whole URL and domain when they switched over to MobileMe. There is nothing we can do about it.
The latest version of the Pedias does indeed change the MobileMe site to the one Apple now prefers, http://web.me.com/
However, if you'd prefer to stick to the old page, http://homepage.mac.com, you can either do a regular HTML export in the Pedias and then manually drag the export folder to your iDisk for upload or you can add a link to your old page to redirect people to the new one at web.me.com.
