2.1.3 rc2 error - tab group

sdk 2.1.3 rc2 ,xcode 4.5 ,iphone 5 simulator ,osx 10.8

This block of code is causing the application to exit on build using 2.1.3 rc2.

This same code works fine on 2.1.3 rc1.

Thanks for any help in advance...

function pub(args) {
 
    var theme = require('theme');
    var config = require('config');
    var win = Ti.UI.createWindow(args);
 
    var tabGroup = Titanium.UI.createTabGroup({
        bottom : -50
    });
 
    var winHome = Ti.UI.createWindow({
        url : '/views/home.js',
        navBarHidden : true,
        tabBarHidden : true,
        title : config.AppName,
        barColor : theme.BarColor,
        backgroundImage : theme.SplashImage,
        layout : 'vertical',
 
    });
 
    var tabHome = Ti.UI.createTab({
        window : winHome
    });
 
    tabGroup.addTab(tabHome);
 
    tabGroup.tabBarVisible = false;
 
    tabGroup.setActiveTab(0);
 
    win.add(tabGroup);
 
    tabGroup.open();
 
    return win;
 
}
 
module.exports = pub;