On my original system, as well on a built-from-scratch system, babel prolog
won't work for me. I've got latest swi-prolog 7.4.0 installed, along with
Emacs 25.1.1, and org 9.0.4, along with ob-prolog 20170102.953, and prolog
(major mode) 1.22. Anything I put in a code block, e.g.,

#+BEGIN_SRC prolog
[likes.pl].
#+END_SRC

results in (*Messages*)

executing Prolog code block...
executing Prolog source code block
org-babel-variable-assignments:prolog: Wrong number of arguments: (1 . 1), 2

Doing C-h f brings up

org-babel-variable-assignments:prolog is a compiled Lisp function in
‘ob-prolog.el’.
(org-babel-variable-assignments:prolog PARAMS)
Not documented.

. . . and I found it in
https://github.com/ljos/ob-prolog/blob/master/ob-prolog.el, but can't
fathom what is going wrong.

Regular, non-org prolog major mode interactions work fine.

I know I try everyone's patience on this list, but I'm trying out many
different languages' babel capabilities -- and reporting my "findings."

LB