Grid load from store error

Hi,

I am looking for some guidance with a very rudimentary issue that has me well stumped.

When I load my form I get the following error "Uncaught TypeError: Cannot read property 'buffered' of undefined "
the code I have is as follows.

Code:

Ext.define('ExtDesktop.view.newUserFrm', {    extend: 'Ext.panel.Panel',
    alias: 'widget.newUsers',


    requires: [
        'ExtDesktop.store.MyUserStore'
    ],


    stateId: 'newUser',
    height: 250,
    width: 594,


    initComponent: function() {
        var me = this;


        Ext.applyIf(me, {
            dockedItems: [
                {
                    xtype: 'toolbar',
                    dock: 'bottom',
                    layout: {
                        pack: 'end',
                        type: 'hbox'
                    },
                    items: [
                        {
                            xtype: 'button',
                            width: 100,
                            iconCls: 'icon-save',
                            text: 'Save'
                        },
                        {
                            xtype: 'button',
                            width: 100,
                            iconCls: 'icon-cancel',
                            text: 'Cancel'
                        },
                        {
                            xtype: 'button',
                            cls: 'btn-help',
                            width: 75,
                            iconCls: 'icon-help',
                            text: 'Help'
                        }
                    ]
                }
            ],
            items: [
                {
                    xtype: 'gridpanel',
                    id: 'userGrid',
                    title: 'My Grid Panel',
                    store: 'usersJsonStore',
                    columns: [
                        {
                            xtype: 'gridcolumn',
                            dataIndex: 'FirstName',
                            text: 'first'
                        },
                        {
                            xtype: 'gridcolumn',
                            dataIndex: 'LastName',
                            text: 'last name'
                        },
                        {
                            xtype: 'gridcolumn',
                            dataIndex: 'Email',
                            text: 'email'
                        }
                    ]
                }
            ]
        });


        me.callParent(arguments);
    }



});

my model

Code:

Ext.define('ExtDesktop.model.userData3', {    extend: 'Ext.data.Model',


    fields: [
        {
            name: 'idClientUser',
            type: 'int'
        },
        {
            name: 'userID',
            type: 'string'
        },
        {
            name: 'FirstName',
            type: 'string'
        },
        {
            name: 'LastName',
            type: 'string'
        },
        {
            name: 'CreateDate',
            type: 'date'
        },
        {
            name: 'ValidTo',
            type: 'date'
        },
        {
            name: 'LastLogin',
            type: 'date'
        },
        {
            name: 'Status',
            type: 'string'
        },
        {
            name: 'Email',
            type: 'string'
        },
        {
            name: 'Password',
            type: 'string'
        },
        {
            name: 'SecToken',
            type: 'string'
        }
    ]

});

and my store

Code:

Ext.define('ExtDesktop.store.usersJsonStore', {    extend: 'Ext.data.Store',


    requires: [
        'ExtDesktop.model.userData3'
    ],


    constructor: function(cfg) {
        var me = this;
        cfg = cfg || {};
        me.callParent([Ext.apply({
            autoLoad: true,
            filterOnLoad: false,
            model: 'ExtDesktop.model.userData3',
            sortOnLoad: false,
            storeId: 'stid1',
            buffered: true,
            proxy: {
                type: 'ajax',
                url: '/data/getUsers.txt',
                reader: {
                    type: 'json',
                    root: 'data'
                }
            }
        }, cfg)]);
    }
});

my json data is

Code:

{    "success" : 1,
    "advisory" : "",
    "records" : 1,
    "fields" : "idClientUser,userID,FirstName,LastName,CreateDate,ValidTo,LastLogin,Status,Email,Password,SecToken",
    "data" : [
                {"idClientUser":16,
                 "userID":"admin",
                 "FirstName":"System",
                 "LastName":"Administrator",
                 "CreateDate":"3/27/2014 2:16:28 PM",
                 "ValidTo":"12/31/2099 11:59:59 PM",
                 "LastLogin":"5/20/2014 9:44:46 PM",
                 "Status":"A",
                 "Email":"admin@webworksonline.com",
                 "Password":"Passw0rd",
                 "SecToken":"111111111111111111111111"
                 },
                 {"idClientUser":17,
                 "userID":"admin2",
                 "FirstName":"System",
                 "LastName":"Administrator",
                 "CreateDate":"3/27/2014 2:16:28 PM",
                 "ValidTo":"12/31/2099 11:59:59 PM",
                 "LastLogin":"5/20/2014 9:44:46 PM",
                 "Status":"A",
                 "Email":"admin2@webworksonline.com",
                 "Password":"Passw0rd",
                 "SecToken":"111111111111111111111111"
                 }
            ]
}

As best I can tell this is not very complex, and my code follows the docs from http://ift.tt/Sl0r8L

Any help would be greatly appreciated,

-Allen