Line number: 6
Error: There is a duplicate ‘system.web.extensions/scripting/scriptResourceHandler’ section defined
This is a known issue with ASP.NET 4.0 / vs 2010
"The workaround for the second scenario is to delete or comment out all the system.web.extensions configuration section definitions and configuration section group definitions from the application-level
file. These definitions are usually at the top of the application-level
file and can be identified by the configSections element and its children."