Ajax paging work for Firefox, not for IE, how to resolve the problem?

Question

I try to implement paging with ajax function. Then I create list view and partial view. Partial view displly data list and paging link List view include keyword for earch and the partial view.

My partial view looks like:

<div id="MyList">
    <div style="text-align: right">
  <% for (int i = 1; i <= (int)ViewData["totalPages"]; i++)
     {%>
  <%= Ajax.ActionLink(i.ToString(), "AjaxList", new { page = i, keyword = ViewData["keyword"] },
 new AjaxOptions { UpdateTargetId = "MyList" }, new { @class = ((i == (int)ViewData["currentPage"]) ? "selected" : "") })%>
  <%} %>
    </div>
...
</div>

The controller action for paging is:

[Authorize]
public ActionResult AjaxList(int? page, string keyword)
{
  var results = repository.FindAll();
  if ((keyword != "") && (keyword != null))
  {
    results = SearchByKeyword(results , keyword);
  }

  int cnt = results .Count();
  ViewData["currentPage"] = page ?? 1;
  ViewData["totalPages"] = (int)Math.Ceiling(1.0 * cnt / PageSize);
  ViewData["keyword"] = keyword;
  var items = results.Skip(((page ?? 1) - 1) * PageSize).Take(PageSize);

  if (Request.IsAjaxRequest())
    return View("MyGrid", items);  // HTML fragment
  else
    return View(items); // Complete HTML page
}

It works fine in Firefor. No error. But it not working in IE(I use IE 7). I got the error as below:

A Runtime Error has occurred. Do you wish to debug? 
Line 17: 
Error:Unknow runtime error

If I choosed debug, the it goes to file MicrosoftAjax.js, in VS 2008, I got error message said

htmlfile: Unknown runtime error

How to fix this problem for IE?