Error message-“The page you are requesting cannot be served because of the extension configuration.”

 this is the  error message  i am  getting when trying to run my application. I don't know how to fix it:

HTTP Error 404.3 - Not Found The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map.

Here's a screenshot of the error page: 

How can I fix this error?