extjs4.0 form数据加载有关问题 _Ajax

extjs4.0 form数据加载问题。
<%@ page language="java" contentType="text/html; charset=UTF-8"

	pageEncoding="UTF-8"%>

<%@ page isELIgnored="false"%>

<%String path=request.getContextPath();	

   %>



<html>

<head>

<title>Test direct(Ext4)</title>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<link rel="stylesheet" type="text/css"

	href="<%=path%>/ext-4.0.1/resources/css/ext-all.css">

<link rel="stylesheet" type="text/css" href="<%=path%>/css/main.css">

<script type="text/javascript" src="<%=path%>/ext-4.0.1/ext-all.js"></script>

<script type="text/javascript" src="<%=path%>/paper/paperApi.js"></script>



<title>在线考试</title>

</head>

<body>

<script type="text/javascript">

Ext.onReady(function(){

	Ext.Direct.addProvider(Ext.paper.REMOTING_API);



	var form=Ext.create('Ext.form.FormPanel', {

		border:false,

		fieldDefaults:{//统一设置表单字段默认属性

			labelSeparator :'：',//分隔符

			labelWidth : 80,//标签宽度

			width : 270,//字段宽度

			msgTarget : 'under'

		},

	    

	    api: {

	        load: paper.load//加载数据的远程方法

	      //提交数据的远程方法

	    },

      //  disabled:true,

       items: [{

           xtype     : 'textfield',

           fieldLabel: '题号',

           name:'id'

          // disabled:true

         

       },{

        xtype     : 'textarea',

        fieldLabel: '题目',

        name:'context'

       // disabled:true

      

    },{

       xtype:'textfield',

       fieldLabel:'A',

       name:'answer1'

      /// disabled:true

        },{

            xtype:'textfield',

            fieldLabel:'B',

            name:'answer2'

        //    disabled:true

         },{

            xtype:'textfield',

            fieldLabel:'C',

            name:'answer3'

         //   disabled:true

            },{

             xtype:'textfield',

             fieldLabel:'D',