title: ASP.NET MVC web.config (multiple) issue
body: <p>i'm having problems running my MVC project on my server. The main project on the server has it's own web.config file (1.0 versions referenced in configsections), while the 'virtual subproject' also has one (3.5 versions referenced). I receive the following error:</p>
  
  <p><em>Configuration Error 
  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: Section or group name 'system.web.extensions' is already defined. Updates to this may only occur at the configuration level where it is defined.</em></p>
  
  <p><strong>Main web.config (location: <code>http://servername/web.config</code>) section:</strong></p>
  
  <p>sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"</p>
  
  <p><strong>Subproject web.config (location: <code>http://servername/subproject/web.config</code>) section:</strong></p>
  
  <p>sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"</p>