Object doesn't support property or method 'addListener' when using borderlayout

[dekely]

Hi All,
I'm using version 2.2.1
whenever I add a panel with region != 'center' I get the following error:

SCRIPT438: Object doesn't support property or method 'addListener'
ext-all-debug.js, line 1236 character 9

Code example:
new Ext.Panel({
renderTo: Ext.getBody(),
layout: 'border',
height: 300,
items: [{
region: 'center',
title: 'north',
margins: '0 0 5 0'
},
{
region: 'east',
title: 'north',
margins: '0 0 5 0'
}]
});

any ideas?