Extjs Cannot read property 'dom' of null - dom

Question

In short, I have a login panel, which will be shown when onClick event is true, but I get error Cannot read property 'dom' of null. When I click second time - the panel is shown, but some elements of it are not shown. When I click for 3th time, the other elements has show, an last, I ger error "Cannot call method 'bringToFront' of undefined".
Ext.onReady(function() {
Ext.QuickTips.init();
Ext.ns('Site.login');
var globalKeyMap = new Ext.KeyMap(document);
globalKeyMap.accessKey = function(key, handler, scope) {
var h = function(n, e) {
e.preventDefault();
handler.call(scope || this, n, e);
};
this.on(key, h, scope);
};
var trackEnter = function(tf, e) {
if (e.keyCode == 13) {
e.stopPropagation();
doLogin();
}
}
var doLogin = function() {
var f = loginPanel.getForm();
if (f.isValid()) {
f.doAction(new Hypo.form.Action.DwrSubmit(f, {
waitMsg: 'Authentication is in progress',
invoker: function(form, cb) {
Login.login(form.getValues(), cb);
},
success: function(fp, o) {
loginForm.hide();
Ext.getBody().addClass("x-body-masked");
var w = loginForm;
w.mask.setSize(Ext.lib.Dom.getViewWidth(true), Ext.lib.Dom.getViewHeight(true));
w.mask.show();
if(o.result.data[0].authorities[0].authority=='ROLE_SUPERVISOR')
{
setTimeout('document.location = "AdminUsers.jsp"');
}
else if(o.result.data[0].authorities[0].authority=='ROLE_ADMIN')
{
setTimeout('document.location = "AdminUsers.jsp"');
}
else
{
setTimeout('document.location = "List.jsp"');
}
}
}));
}
}
var loginPanel = new Ext.FormPanel({
id: 'loginPanel',
labelWidth: 75, // label settings here cascade unless overridden
frame: false,
border: false,
bodyStyle:'padding:5px 5px 0',
width: 350,
defaults: {
width: 230
},
defaultType: 'textfield',
autoHeight: true,
items: [{
id: 'idxLogin',
fieldLabel: 'Login',
name: 'login',
allowBlank: false,
enableKeyEvents: true,
maxLength: 50,
listeners: {
'keypress': trackEnter
}
}, new Ext.form.TextField({
fieldLabel: 'Password',
name: 'password',
inputType: 'password',
enableKeyEvents: true,
maxLength: 50,
listeners: {
'keypress': trackEnter
}
})
]
});
var loginForm = new Ext.Window({
layout : 'fit',
width : 350,
closable : false,
modal: true,
plain : true,
title: 'User Authentication',
items: loginPanel,
autoHeight: true,
buttons: [{
text: 'OK',
handler: doLogin
},{
text: 'Cancel',
handler: function() {
loginForm.hide();
}
}],
listeners: {
'activate': function() {
setTimeout(function() {
Ext.getCmp("idxLogin").focus();
}, 100);
}
}
});
Site.login.window = loginForm;
});
Login
I tryed to add renderTo:'someDiv' and add to body a div with id "someDiv". But I received the same error message.
Please, help with that.