为什么绑定xml文件到TreeNodeSrc属性后，老是出现"The data at the root level is invalid. Line 1, position 1."异常...

xml内容:
<?xml version="1.0"?>
<TREENODES>
  <TREENODE TEXT="スーバーユーザ">
    <TREENODE TEXT="プロジェクト" />
    <TREENODE TEXT="アプリケーション" />
  </TREENODE>
</TREENODES>aspx.cs内容：
<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="WebApplication1.WebForm1" %>
<%@ Register TagPrefix="iewc" Namespace="Microsoft.Web.UI.WebControls" Assembly="Microsoft.Web.UI.WebControls, Version=1.0.2.226, Culture=neutral, PublicKeyToken=31bf3856ad364e35" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>WebForm1</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<FONT face="MS UI Gothic">
<iewc:TreeView id="TreeView1" runat="server" TreeNodeSrc="TreeData.xml"></iewc:TreeView></FONT>
</form>
</body>
</HTML>
一直会出现[The data at the root level is invalid. Line 1, position 1.]这个异常
各位老大,来看看怎么回事啊?