title: How do I fix 'Unprocessed view path found' error with ExceptionNotifier plugin in rails 2.1?
body: <p>After upgrading a rails 1.2 website to 2.1, the <a href="http://agilewebdevelopment.com/plugins/exception_notifier" rel="noreferrer">ExceptionNotifier plugin</a> no longer works, complaining about this error:</p>
  
  <blockquote>
    <p>ActionView::TemplateFinder::InvalidViewPath:  Unprocessed view path
    found:
    "/path/to/appname/vendor/plugins/exception_notification/lib/../views".
    Set your view paths with #append_view_path, #prepend_view_path, or #view_paths=.</p>
  </blockquote>
  
  <p>What causes it and how do I fix it?</p>