Hi scottmcclean, I am not an expert but that looks like you have got some files in the wrong place probably when you copied the files over originally for the worldpay module. If I were you I would roll it back to a previous state and then try again (hopefully you backed up all your site files locally before you added the module :-) Looks like something is not defined so it is displaying the tag it is looking for. I can assure you, the Worldpay module works if you install it as per instructions as it worked for me first time. Also good luck with the displaying of your payment receipt...see the last 30 or so pages in this forum.
I now always do a full website back up including the current .sql database file everytime I make a major change. If you don't do that you may end up having to start from scratch.