My system: I have installed Windows 7, VS2010 and .NET40 and ASPAJAXExtSetup.msiI'm getting the error below. Error Summary HTTP Error 500.19 - Internal Server Error The requested page cannot be accessed because the related configuration data for the page is invalid. Detailed Error Information Module IIS Web Core Notification Unknown Handler Not yet determined Error Code 0x80070032 Config Error The configuration section 'system.web.extensions' cannot be read because it is missing a section declaration Config File \\?\C:\inetpub\tickets\web.config