Hi,

I am looking for a working configuration for using oz code blocks in org-mode file. I've installed Mozart2 on macOS 10.12.6 and use org-mode version 9.0.9. I've put
(org-babel-do-load-languages
 'org-babel-load-languages
 '((emacs-lisp . t)
   (oz . t)))
into my Aquamacs initialization and the ob-z.el in a path where Emacs can read it.
If I try to execute (C-C C-C) the following code block

#+begin_src oz :results value
  39 + 3
#+end_src

I get the following error messages:

executing Oz code block...
Org-babel: executing Oz expression
Create OPI socket for evaluating expressions
open-network-stream: make client process failed: Connection refused, :name, *Org-babel-OPI-socket*, :buffer, nil, :host, localhost, :service, 6001, :nowait, nil

I cannot figure out, what to do?
Any hints?

Johannes