title: RadAjaxManager AjaxRequest TypeError: Cannot read property 'id' of undefined
body: <p>Here's the situation:<br>
  I have a host page that loads a custom web user control.  In my web control I want use javascript and a RadAjaxManager to load up a second web user control.  I used this example from Telerik as my guide:<br>
  <a href="http://demos.telerik.com/aspnet-ajax/ajax/examples/manager/clientsideapi/defaultvb.aspx" rel="noreferrer">http://demos.telerik.com/aspnet-ajax/ajax/examples/manager/clientsideapi/defaultvb.aspx</a></p>
  
  <p>However, I kept getting the following error when I would call the client-side "ajaxRequest" method on the RadAjaxManager.</p>
  
  <pre><code>TypeError: Cannot read property 'id' of undefined
  </code></pre>