Ext4.0.7使用Ext.grid.ColumnModel报错：TypeError: Ext.grid.Model is not a constructor

Ext.onReady(function(){
　　　　　　　//定义列
var cm = new Ext.grid.ColumnModel([
{header: '编号', dataIndex: 'id'},
{header: '名称', dataIndex: 'name'},
{header: '描述', dataIndex: 'des'}
]);

//数据定义
var data = [
['1001','name1','description1'],
['1002','name1','description1'],
['1003','name1','description1'],
['1004','name1','description1'],
['1005','name1','description1']
];

//数据源定义
var store = new Ext.data.Store({
proxy: new Ext.data.MemoryProxy(data),
reader: new Ext.data.ArrayReader({},[
{name: 'id'},
{name: 'name'},
{name: 'des'}
])
});
store.load();

//grid panel
var grid = new Ext.grid.GridPanel({
renderTo: Ext.getBody(),
store: store,
cm: cm
});
});

Ext.onReady(function(){
　　　　　　　　Ext.create('Ext.data.Store', {
storeId: 'simpleStore',
fields: ['name', 'email', 'phone'],
data:{
'items':[
{'name':'yanshiying', 'email':'email', 'phone':'1234567890'},
{'name':'yanshiying', 'email':'email', 'phone':'1234567890'},
{'name':'yanshiying', 'email':'email', 'phone':'1234567890'}
]
},
proxy: {
type: 'memory',
reader: {
type: 'json',
root: 'items'
}
}
});

Ext.create('Ext.grid.Panel', {
title: 'Simple',
store: Ext.data.StoreManager.lookup('simpleStore'),
columns: [
{header: 'Name', dataIndex: 'name'},
{header: 'Email', dataIndex: 'email'},
{header: 'Phone', dataIndex: 'phone'}
],
height: 200,
width: 400,
renderTo: Ext.getBody()
});
})