I am not entirely sure on the specific workings of the rag-doll entity (if it is set up as a standard prop the following should work though). The ropeNode should have "Start Body" and "End body" fields - which you will need to enter your ragdoll entity into one of (and your wall or block_box into the other). The original position of the pos-node relative to the body is used as the attach point. For example, if I had a coin and placed a rope connecting to the heads side, the rope would always try to be attached to the heads side. Note that the rope doesn't have collision detection as far as I am aware.
Answer To old question regarding what block_boxes do:
If you edit your post to add a new question - would you kindly leave the original post quoted or in spoiler tags so that others with a similar problem, if searching, find the thread. Of course, if your problem is separate you are still encouraged to open a new topic.