Error: Unrecognized attribute 'xmlns'. Note that attribute names are case sensitive

Visual Web Developer 2008 After publishing a newly created website to an existing server (after updating the .NET framework). I browse to the website from my workstation and get:

Error: Unrecognized attribute 'xmlns'. Note that attribute names are case sensitive

...in this file:

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG\web.config

Here is what to do.

1. Edit the web.config file (get the filename from the bottom of the error message) . Make sure you're opening the version on the SERVER, not your local workstation.
2. find every occurrence of the text xmlns="", and DELETE it. Do NOT delete the line that has a long filename in the "" marks.
3. Save.
4. Go back to your workstation and refresh the browser.

After a long time, it refreshed for me. It was like the webserver had to re-initialize first. Then it started acting normally.