title: Strange Error - CS0012: The type x is defined in an assembly that is not referenced
body: <p>The type 'x' is defined in an assembly that is not referenced. You must add a reference to assembly 'abc123'.</p>
  
  <p>I have a .NET 2.0 web application that references my assembly 'abc123'.  The assembly exists in the GAC and I've verified that it is the correct(same) version.  The rest of application has no issues except for one .aspx page.  The page in question has a repeater that displays a user control as one of its "fields".  Upon binding a list of type y to the repeater I pass the user control a list of type x (a property of y) as shown here:</p>
  
  <pre><code>&lt;uc1:usercontrol id="ucusercontrol " runat="server" myPublicUserControlProperty='&lt;%#Eval("CollectionOfX") %&gt;'/&gt;
  </code></pre>
  
  <p>On the user control's property set, I bind the list of type x to a gridview in the user control.</p>
  
  <p>One strange thing to note is that this report works fine on my development pc but not on any servers once I deploy.  My pc is Windows XP, IIS6, VS2005.  The servers are Windows Server 2003, IIS6.</p>
  
  <p>I hope I explained that well enough.  Thanks in advance for any insight you can provide.</p>