title: Show Visualizers Error "could not load this custom viewer"
body: <p>When I try to inspect DataSet by standard DataSet visualizer I see this error <strong>"could not load this custom viewer"</strong>. 
  I wrote simple dataset visualizer, but error throws anyway too.</p>
  
  <p>On other computers with the same configuration visualizer show without any errors.</p>
  
  <p>OS: <strong>Windows 7 x86 (Release)</strong></p>
  
  <p>VS: <strong>Visual Studio 2010 RC</strong></p>
  
  <p>has somebody any ideas?</p>
  
  <p>I reinstall VS with no effect.</p>