I'm afraid this is the first I've heard of a "4" flavoured Blosxom. Try dropping the "/+4" bit from the end of the URL.
Somehow I noticed that the blog in which this cartoon was posted in is powered by Blojsom, a Blosxom derivative written in Java (and nowadays database powered). I already have heard of a lot of blogging software which works similar to Blosxom and often is also named similar, e.g. Pyblosxom or Blosxonomy, but Blosjom hasn’t been noticed by yet although it is mentioned in Children of Blosxom where I first noticed Blosxonomy.
So far, so good, but what really surprised me is that a blog engine developed after Blosxom’s ideas officially made into MacOS X 10.4 Server. (BTW at a time, I neither had a blog nor knew about Blosxom. :-)