ASP.NET MVC Ajax.BeginForm не работает

<script src="../../Scripts/MicrosoftAjax.debug.js" type="text/javascript"></script>

<script type="text/javascript">
    function loginOK()
    {
        var item = document.getElementById('statusLabel');
        item.innerHTML = "OK";
        document.getElementById('LoadImg').style.visibility = 'hidden';
    }

    function process()
    {
        var lab = document.getElementById('statusLabel');
        lab.innerHTML = 'Checking...';
        lab.style.color = 'Black';
        document.getElementById('LoadImg').style.visibility = 'visible';
    }

    function fail()
    {
        var lab = document.getElementById('statusLabel');
        lab.innerHTML = 'Login is being used';
        lab.style.color = 'Red';
        document.getElementById('LoadImg').style.visibility = 'hidden';
    }
</script>

 <div style="width:30%; float:left;">
     <label for="Login">Login:</label>
     <%= Html.TextBoxFor(model=>model.Login) %>
     <%= Html.ValidationMessageFor(model=>model.Login) %>

     <img id="LoadImg" alt="" src="../../Content/Images/ajax-loader.gif" style="visibility:hidden;"/>
     <br />
     <label id="statusLabel" />
     <br />
     <%=Ajax.ActionLink("CheckLogin","CheckLoginAvailability", "Account",
        new AjaxOptions { UpdateTargetId = "statusLabel", OnBegin = "process", OnFailure = "fail", OnSuccess="loginOK"})%>
 </div>

и в AccountController:

    [AcceptVerbs(HttpVerbs.Post)]
    public void CheckLoginAvailability(string login)
    {
        //do some job
    }

И FireBug сообщает, что / Account / CheckLoginAvailability не найден. Кроме того, после обратного вызова этот ActionLink скрыт. Почему?