It shouldn't add a piece of grey code, it should add an entire cart display with all the items in the cart listed, a sub-total and total and update functionality to update quantity and remove items. Something is wrong in the Display Cart step.
Does the display manager open? Are there any errors or messages? The real problem here is that the display manager isn't running correctly. If you post a US phone number or Skype contact information I can set up a screen sharing session so you can show me what you are seeing. I've never heard of a problem like yours, so I'll have to debug it directly to figure out what is going on.