Error PhoneGap Build + Cordova + ChildBrowser

Here is my code:

<script src="include/cordova.js" type="text/javascript"></script> <script src="include/sencha-touch-all.js" type="text/javascript"></script> <script type="text/javascript" charset="utf-8" src="include/childbrowser.js"></script> <link href="include/sencha-touch.css" rel="stylesheet" type="text/css" />

var childBrowser = null;
if (navigator.userAgent.match(/(iPhone|iPod|iPad|Android|BlackBerry)/)) {
   document.addEventListener("deviceready", onDeviceReady, false);
} else {
onDeviceReady();
}
function onDeviceReady(){
  console.log("PhoneGap is Ready");
  childBrowser = ChildBrowser.install();
}
function openChildBrowser(url)
{
        try {
            //both of these should work...
            var cb = new ChildBrowser();
            console.log(cb);
            cb.showWebPage('http://www.google.com');
        }
        catch (err)
        {
            alert(err);
            console.log(err);
        }
}

...

There is another code that is not related, but when I call openChildBrowser(), I get the following error:

Uncaught TypeError: Object #<Object> has no method 'exec' I believe this is a reference to a childbrowser call that calls exec on an object cordova.

When I look at an object cordvoa, I do not see the function execanywhere ...

Any ideas?