Dragging an ImageView using touch events

I am working on a tutorial and it is not behaving correctly. I think it should be a fairly simple fix but I am new to the program so I may be wrong.

The tutorial is located at : http://www.packtpub.com/article/appcelerator-titanium-creating-animations-transformations-understanding-drag-drop

In the section "Dragging an ImageView using touch events, the first step is to make the image drag using the code:

imageViewFace.addEventListener('touchmove', function(e){
  imageViewMe.left = e.x;
  imageViewMe.top = e.y;
});

This code works but pulls the image from the top corner, so the next set of code is supposed to allow you to drag the image from it's center point. The code in the tutorial is...

imageViewFace.addEventListener('touchstart', function (e) {
  imageViewMe.ox = e.x - imageViewMe.center.x;
  imageViewMe.oy = e.y - imageViewMe.center.y;
});
 
imageViewFace.addEventListener('touchmove', function(e){
  imageViewMe.center = {
    x:(e.x - imageViewMe.ox),
    y:(e.y - imageViewMe.oy)
  };
});

However, when I run this code in the emulator, it doesn't drag at all. Does anyone know why this isn't working and what I could change to make it function? As I said, I'm new to the program... so any good tutorials on these and similar animations would also be helpful.

Many thanks, Andi

I'm actually using the iPhone simulator (sorry I wasn't clear). It doesn't seem to be an issue with slow performance as the first section of code works and the second doesn't function at all.

This might help on the drag&drop issue: http://developer.appcelerator.com/question/58211/spinning-images-and-dragdrop