Email shortcodes not working

I have been trying to get the email short codes to work consistently for some time now. I have used the shortcodes from the knowledge base but they do not seem to work for me. I have had the (username) code working and now it has stopped? I have never been able to get some of the others to work at all, for example (website) I have set up a test listing in my DP install with all the required fields filled in but the email is sent with no data from the shortcodes. I really am interested in the (website) shortcode for notifying customers about expiring listings. Please can anyone tell me where I can look to sort this out.