title: SL 4 Version Hell? The silverlight developer runtime is not installed please install a matching version
body: <p>I've been developing for and running Silverlight 4 for about a week.  A week ago I installed the Silverlight 4 design time components to develop and debug silverlight for VS 2010 - I posted some of these apps and they were used by users running SL4.  Today, I went to a website that told me to upgrade my SL (I think it was the MS expression site) - so I did that and all the sudden I get this error when running SL 4 apps within VS 2010.</p>
  
  <p>The silverlight developer runtime is not installed please install a matching version</p>
  
  <p>Installing the latest version of the Silverlight SDK does not correct this.  Basically I am stuck and unable to run Silverlight apps from VS2010.</p>
  
  <p>Are versioning problems like this a common theme in SilverLight?  The only thing I can think of is that there is a minor version difference between the versions used on the the MS Expression web site and the version (SL4) I installed from MS site a few days ago?  However re-installing the latest version of SL4 does not correct this.</p>
  
  <p>Any help?</p>