Sencha Touch first run Messagebox Error
===

I've just installed Sencha on Eclipse and build hello world app,
The is RUNNING OK, but the Message boxes don't work:

    Ext.setup({
        onReady: function() {
           if (Ext.is.Android) 
	      Ext.Msg.alert("INFO", "Welcome Android user!"); 	
           if (Ext.is.Blackberry)
	      Ext.Msg.alert("INFO", "Welcome Blackberry user!");
             if (Ext.is.iPad)
	        Ext.Msg.alert("INFO", "Welcome iPad user!");
           }
         });

The Error that I get in the eclipse log:

>  E/Web Console(279): Error: [ERROR][Anonymous] Using Ext.Msg without requiring Ext.MessageBox at file:///android_asset/www/senchatouch/src/log/writer/Console.js?_dc=1342002536493:17


I can't figure what is wrong,
Thanks.