What's wrong with my syntax? -Ext JS

What's wrong with my syntax? -Ext JS

I'm having a syntax issue here in my Ext application. I assume it's syntax
because it works fine in Firefox but not Internet Explorer
layout: 'vbox',
tbar: Ext.create('AM.view.TopToolbar', {}), //Trouble Code
items: [ ...
Any ideas?
Error in IE:
SCRIPT16389: Unspecified error.
ext-all-debug.js, line 5017 character 17
app/view/TopToolbar.js:
Ext.define('AM.view.TopToolbar', {
extend: 'Ext.Toolbar',
alias: 'widget.toptoolbar',
defaults: { arrowCls: '' }, //Removing black arrow from toolbar items
items: [
{ text : 'Tools' }
]
}); // this is the entire toolbar so far