A problem which recurs periodically with ComponentLoader

I have a model that represent image which should be displayed.

Code:

Ext.define('ItemModel', {
    extend: 'Ext.data.Model',
    idProperty: 'itemModel',
    fields: [{
        name: 'id',
        type: 'int'
    },{
        name: 'src',
        type: 'string'
    }]
});

I'm using a 'store' with a 'reader' to add imaged on panel:

Code:

var previews = Ext.create('Ext.Panel',{
    layout: 'column',
    height: 500,
});

Ext.define('ItemModelStore', {
    extend: 'Ext.data.Store',
    model: 'ItemModel',
    proxy: {
        type: 'ajax',
        url: 'php/read.php',
        reader:{
            type:'json',
            root: 'objs'
        }
    }
});

var itemModelStore = Ext.create('ItemModelStore');
itemModelStore.load(function() {
    itemModelStore.each(function(record){
        previews.add({
            'id': record.get('id'),
            'xtype': 'image',
            'src': record.get('src'),
            'style' : 'padding-left:5px;padding-top:5px;cursor:pointer;',
            listeners: {
                el: {
                    click: function() {
                        albumId = record.get('id');
                        var tabs = Ext.getCmp('tabs');
                        tabs.remove('albumsTab', true);
                        tabs.remove('photosTab', true);
                        tabs.add({
                            title: 'New album',
                            items: [
                            {
                                xtype: 'panel',
                                layout: {
                                    type: 'vbox',
                                    align: 'stretch'
                                },
                                items: [
                                    uploadForm
                                ]
                            }
                            ]
                        });
                    }
                }
            }
        });
    });
});
previews.doLayout();

In a first time loading a page displayed fine. But if I reload page, periodically the error occurs in 37654 row of ext-all-dev.js:

TypeError: me.el is null me.container = Ext.get(me.el.dom.parentNode);

JSON retrieved from server is looks like this:

{"objs":[{"id":"1","src":"img\/newalbum.png"},{"id":"2","src":"img\/newalbum1.png"}]}

I'm using Ext JS 4.1.