How to solve Ajaxcontroltoolkit Editor didn't display some icon ??

Question

Hello everyone!
Last time i use Editor of ajaxcontroltoolkit is very fine.But now i have just this error on browser when i run Editor.This is picture of result when i run on Firefox 5.0.1 version:


And this is result when i run IE 8:

And code:I using usercontrol
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="ajaxcontroltoolkit_Editor.ascx.cs" Inherits="user_control_ajaxcontroltoolkit.controls.ajaxcontroltoolkit_Editor" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit.HTMLEditor"
    TagPrefix="cc1" %>
<div id="editor_ajaxcontroltoolkit">
    <ajax:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
    </ajax:ToolkitScriptManager>
    <cc1:Editor ID="Editor1" runat="server" />
</div>

I use Ajaxcontroltoolkit 4 and visual 2010.

I don't khow to fix it.Please tell me know .Thanks for watching!!