Thanks so much for your response. This is a very frustrating error. This kind of great support is a wonderful thing.
If this were not a proper web address, wouldn't I be unable to connect to the server when I click TEST on setting up the server? When I click TEST, I get the notification "Dreamweaver connected to your server successfully."
Also, everything I do is at public_html as site root, so my server root directory is set to /public_html. Is this wrong? (It still tests as connecting successfully.)
The testing server duplicates the main server, only the checkboxes Remote and Testing are different on the Site Setup panel.
Thanks again for your help.