ASP.NET 4.0 application error: Unrecognized attribute 'targetFramework'

You may experience the following error when you attempt to open your web application:

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive.
 

The error indicates that your account is configured to run with the ASP.NET 2.0 framework, but your application is an ASP.NET 4.0 application.