Adam,
Yes, I have it setup to notify me when there is a post. As soon as I got your post I followed the link you provided and downloaded that package. I extracted everything and loaded it up into my DNN 5.0 installation. I added the code to my web.config and tried to hit the site. I got the same error, so I went back into the web.config and changed the default HTML provider back to the FCK. I was able to access my site again.
Thank you!