ext2.2分页出现脚本错误，等待受教！

脚本提示为：
行:11
字符:12246
代码:0
错误:系统错误: -1072896658。
网址:http://localhost:8088/Test/paging.jsp

源码为：
<%@ page language="java" pageEncoding="utf8"%>
<%
String start = request.getParameter("start");
String limit = request.getParameter("limit");
try {
int index = Integer.parseInt(start);
int pageSize = Integer.parseInt(limit);

String json = "{totalProperty:100,root:[\n";
for (int i = index; i < pageSize + index; i++) {
    json += "{id:" + i + ",name:'name" + i + "',descn:'descn" + i + "'}";
    if (i != pageSize + index - 1) {
        json += ",\n";
    }
}
json += "]}";
response.getWriter().write(json);
System.out.println(json);

} catch(Exception ex) {
}
%>

paging.jsp

<br> Ext.onReady(function(){<br> var cm = new Ext.grid.ColumnModel([<br> {header:&#39;编号&#39;,dataIndex:&#39;id&#39;},<br> {header:&#39;名称&#39;,dataIndex:&#39;name&#39;},<br> {header:&#39;描述&#39;,dataIndex:&#39;descn&#39;}<br> ]);</p> <pre><code>var ds = new Ext.data.Store({ proxy: new Ext.data.HttpProxy({url:&quot;paging.jsp&quot;}), reader: new Ext.data.JsonReader({totalProperty: &#39;totalProperty&#39;,root: &#39;root&#39;}, [ {name: &#39;id&#39;}, {name: &#39;name&#39;}, {name: &#39;descn&#39;} ]) }); var grid = new Ext.grid.GridPanel({ el: &#39;grid&#39;, ds: ds, cm: cm, tbar: new Ext.PagingToolbar({ pageSize: 5, store: ds, displayInfo: true, displayMsg: &#39;显示第 {0} 条到 {1} 条记录，一共 {2} 条&#39;, emptyMsg: &quot;没有记录&quot; }), bbar: new Ext.PagingToolbar({ pageSize: 5, store: ds, displayInfo: true, displayMsg: &#39;显示第 {0} 条到 {1} 条记录，一共 {2} 条&#39;, emptyMsg: &quot;没有记录&quot; }), height:250, width:600, title:&#39;Array Grid&#39; }); grid.render(); ds.load({params:{start:0,limit:10}}); </code></pre> <p>})<br>

请问怎么解决！！

后台的数据格式如下：
{
"beans" : [{
"name" : "3m Co.",
"id" :1,
"descn" : 'xxx'
},{
"name" : "Apple.",
"id" :2,
"descn" : 'yyy'
}],
count : 100
}