title: System.DirectoryServices is not recognised in the namespace 'System'
body: <p>I'm trying to use <code>System.DirectoryServices</code> in a web site project and I'm getting this error:</p>
  
  <blockquote>
    <p>The type or namespace name 'DirectoryServices' does not exist in the namespace 'System' (are you missing an assembly reference?)</p>
  </blockquote>
  
  <p>My project has a reference to <code>System.DirectoryServices</code> in <code>web.config</code>:  </p>
  
  <pre><code>&lt;add assembly="System.DirectoryServices, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;  
  </code></pre>
  
  <p>And I do have <code>using System.DirectoryServices</code> in the files where I want to use it.</p>
  
  <p>Does anybody have a clue where to look for the problem?</p>