Compiled ExtJs application throws 'TypeError: Ext.util is undefined' at startup

I've been working on an extjs application for a few weeks now and I'm finally starting to get to a point where I want publish my application. Using Sencha Cmd I've compiled my application into an index.html / all-classes.js without minification. I have a build.bat file the my extjs application root along side with my app.js, in ./app/ are the remaining files of my applications and in ./ext-4.0/ are my ext-js 4.2.1 files.

However, whenever I open the compiled application page in Firefox it throws the following error:

TypeError: Ext.util is undefined

Ext.util.DelayedTask = function(fn, scope, args, cancelOnDelay) {

Whenever I click through I jumps into the all-classes.js to the location where Ext.util.DelayedTask is defined in source in the all-classes.js.

This is head-section my index.html:

Code:

        
        <!-- <x-compile> -->
            <!-- <x-bootstrap> -->
                <script type="text/javascript" src="ext-4.0/locale/ext-lang-nl.js"></script>
                <script type="text/javascript" src="ext-4.0/ext-all.js"></script>
            <!-- </x-bootstrap> -->

            <script type="text/javascript" src="mzPivotGrid-all.js"></script>
            <script type="text/javascript" src="app.js"></script>
        <!-- </x-compile> -->

And this is how I compile my application using a build.bat located in the same folder as app.js:

sencha compile -classpath=ext-4.0/src,. page -in=index.html -out=build/index.html

What an I doing wrong?