asp.beginForm gives "_this._webRequest.completed(Sys.EventArgs.Empty)" when i try to use return RedirectToAction in the controller.

Hi, 
   
  I have a two forms. This one is called CompanyForm.ascx ..      
 <% using (Ajax.BeginForm("CompanyForm",    new AjaxOptions { UpdateTargetId = "sCompanyForm", OnComplete = "Checkupdate", OnSuccess = "ClearData" }))
   {
%>
    <div id="sCompanyForm">
        <% Html.RenderPartial("CompanyData"); %>
    </div>
<% } %>
My next form is the CompanyData.ascx ...
   <%= Html.ValidationSummary("New Company not added, Please correct the errors and try again.") %>
  <p>
  <input type="submit" value="Save" />             
  <%= ...