for me it only works when I have the scripts in this order (so first the microloader):

<script id="microloader" type="text/javascript" src="sdk/microloader/development.js"></script>


<script type="text/javascript" charset="utf-8" src="resources/js/cordova-1.8.1.js"></script>
<script type="text/javascript" charset="utf-8" src="resources/js/TwitterPlugin.js"></script>
<script type="text/javascript" charset="utf-8" src="resources/js/ChildBrowser.js"></script>
<script type="text/javascript">

//this index is for iOS only

function onBodyLoad() {
document.addEventListener("deviceready", onDeviceReady, false);
}

function onDeviceReady() {
//cordova stuff
}

</script>