Problem with pengine_rpc() call. Target app works from browser, but not from that call

Help!
1

I’m using: SWI-Prolog version 8.0.2

I have Pengines up and running successfully. If I point to the Pengines URL in my browser, the main page loads fine. I can then link to the Genealogist app and successfully run queries there.

However, if I try to execute a call from an SWI-Prolog interpreter window, it tells me that it can’t find the genealogist app:

pengine_rpc('http://localhost:3030', ancestor_descendant(X, Y), [       application(genealogist)   ]).

I also tried prepending the app name to the query:

pengine_rpc('http://localhost:3030', genealogist:ancestor_descendant(X, Y), [       application(genealogist)   ]).

But I still get an existence error.

Can anyone tell me why it works from the browser but not from the interpreter?

NOTE: I tried the test again on my Linux box where things seem to work better but in this case they did not. When I execute a ancestor_descendant(X, Y) call on that box, the same call that works from a browser, I get the following error:

?- pengine_rpc('http://localhost:3030', ancestor_descendant(X, Y), [
|           application(genealogist)
|       ]).
ERROR: procedure `'c3e42777-26f7-4dcf-b9a2-4276f540f998':ancestor_descendant(A,B)' does not exist
^  Exception: (9) setup_call_catcher_cleanup('<garbage_collected>', pengines:wait_event(v(_6, _8), destroy(true), [listen('c3e42777-26f7-4dcf-b9a2-4276f540f998'), timeout(300), application(genealogist)]), _138, pengines:pengine_destroy_and_wait(destroy(true), 'c3e42777-26f7-4dcf-b9a2-4276f540f998', _138)) ?