Invalid method (createTabGroup) passed to UIModule

I need to add a TabGroup to an app that was already created a couple weeks back, that only has one window at the time of development (change of plans). When I test the following code to create a new self standing TabGroup on a clean build, it works fine. However if I delete everything out of my older build and just drop the same code into the app.js I get the following error:

[WARN] attempted to load: TiUITabGroupProxy [ERROR] Script Error = invalid method (createTabGroup) passed to UIModule at app.js (line 1).

var tabGroup = Ti.UI.createTabGroup();
 
var myOnlyWin = Ti.UI.createWindow({
    backgroundColor: '#FFF',
    title:'Just Messing around',
    tabBarHidden:true
});
 
 
var tab = Ti.UI.createTab({
    title:"Doesn't matter",
    window: myOnlyWin
});
 
tabGroup.addTab(tab);
tabGroup.open();

I'm hoping to patch over the older version and just bump the current single window into the TabGroup so we can start offering a info button on the top right side of the window (tab).