SplitView - The proxy [object TiUIiPhoneNavigationGroup] does not conform to TiUIViewController protocol

Hey, everyone, I hope you can help me with this:

i Work with OSX 10.8.4, Titanium SDK 3.1.2.G.A Xcode 4.6.3 iOS 6.1

This is my code:

var self = Ti.UI.currentWindow;
 
var win = Ti.UI.createWindow({ backgroundColor : 'white '});
var win2 = Ti.UI.createWindow({ backgroundColor : 'white '});
 
var nav = Ti.UI.iPhone.createNavigationGroup({
   window: win
});
var nav2 = Ti.UI.iPhone.createNavigationGroup({
   window : win2
});
 
var splitView = Ti.UI.iPad.createSplitWindow({
    detailView: nav,
    masterView: nav2
});
 
splitView.addEventListener('visible',function(e){
    if (e.view == 'detail'){
        e.button.title = "Master";
        win.leftNavButton = e.button;
    } else if (e.view == 'master'){
        win.leftNavButton = null;
    }
});
 
 
self.add(splitView);
splitView.open();

[WARN] :   SplitView - The proxy [object TiUIiPhoneNavigationGroup] does not conform to TiUIViewController protocol.
[WARN] :   SplitView - The proxy [object TiUIiPhoneNavigationGroup] does not conform to TiUIViewController protocol.
[WARN] :   TiViewController - The proxy [object TiUIiPhoneNavigationGroup] is not of type TiWindowProxy.
[WARN] :   TiViewController - The proxy [object TiUIiPhoneNavigationGroup] is not of type TiWindowProxy.

Thanks!.