how unlimited size of file download in AjaxFileUpload

hi

i'm using AjaxFileUpload  and when i want to download file  size biger than 7MB

but i see error from AjaxFileUpload 

how can i set size of file to download in AjaxFileUpload 

 <cc1:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server"></cc1:ToolkitScriptManager>
    <div>
  <cc1:AjaxFileUpload ID="AjaxFileUpload1"
    ThrobberID="myThrobber"
    AllowedFileTypes="jpg,jpeg,doc,docx,pdf,zip,rar"
    MaximumNumberOfFiles="2"
    OnClientUploadComplete="uploadComplete"
    OnClientUploadError="uploadError"
    OnUploadComplete="AjaxFileUpload_UploadComplete"
    runat="server"/>
    </div>

string filePath = Server.MapPath("~//pic//") + e.FileName;
        AjaxFileUpload1.SaveAs(filePath);

please F1F1F1F1F1F1F1F1