title: Problem with Ajax.ActionLink
body: <p>i am reading the <strong>professional asp.net mvc</strong> book and implement the <strong>nerd Dinner</strong> example 
  and when start to use Ajax :</p>
  
  <pre><code>&lt;%: Ajax.ActionLink( "RSVP for this event",
                               "Register", "RSVP",
                               new { id=Model.DinnerID }, 
                               new AjaxOptions { UpdateTargetId="rsvpmsg" }) %&gt; 
                                  &lt;% } %&gt;
  </code></pre>
  
  <p>all right,  but when click on "RSVP for this event" link the IE display error message :</p>
  
  <blockquote>
    <p>"Sys is undefined"</p>
  </blockquote>
  
  <p>and when click debug it refer to the line :</p>
  
  <pre><code>&lt;a href="/RSVP/Register/4" onclick="Sys.Mvc.AsyncHyperlink.handleClick(this, new Sys.UI.DomEvent(event), { insertionMode: Sys.Mvc.InsertionMode.replace, updateTargetId: &amp;#39;rsvpmsg&amp;#39; });"&gt;RSVP for this event&lt;/a&gt; 
  </code></pre>
  
  <p>i know that "Sys" should be "System" but how to fix that .</p>
  
  <p>thnks</p>