title: Could not load type 'System.Reflection.IntrospectionExtensions' from assembly 'mscorlib
body: <p>I'm using Unity IoC (Microsoft.Practices.Unity) and I can compile fine, but I'm getting the following error at run time:</p>
  
  <pre><code>Could not load type 'System.Reflection.IntrospectionExtensions' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.
  </code></pre>
  
  <p>The Unity version is: 3.0.1026.0</p>
  
  <p>Is there a compatibility problem between .Net 4 and this version of Unity. Also, I get the same error when using Unity v2. If so, how might I go about resolving this issue?</p>
  
  <p><strong>EDIT:</strong>
  Also, I've verified that mscorlib is referenced in my project.</p>