window.location will hang forever if ExtJS loaded

I found a issue in EnvJS (Version 1.6) in combination with EXTJS.
I do following steps:

// LOAD env js
// Load some page ... cool works.
window.location = "http://localhost/index.html";

// Load Ext js libs...
load("./ext-base.js");
load("./ext-all.js");

// Load another web page..
window.location = "http://localhost/index2.html";
// Hangs forever....

I have absoutle no clue what is going on there.

Version:

Envjs.version = "1.6";//?
Envjs.revision = '';
/
  Envjs core-env.1.2.13 
  Pure JavaScript Browser Environment
  By John Resig <http://ejohn.org/> and the Envjs Team
  Copyright 2008-2010 John Resig, under the MIT License
 /

I'm thankfull for any help
chilicat