[Jprogramming] error with Graphviz and/or webview in j901 under Windows 10

['Michael Day' via Programming]

Wishing to visualise a set of pairs of integers as a graph,  I 
discovered graphviz
hiding among the addons.
I think I've installed it - ie update the addon,  and then:

    load 'c:/d/j901/addons/graphics/graphviz/graphviz.ijs'
    getbin_pgraphview_''
Graphviz binaries installed.

But then:

    graphview''
|cc : child not supported: webview
: wd
|   (LF,~wd ::(''"_)'qer')    (13!:8)3

So I looked around for help - first I noticed the folder testsm - no idea
if it's relevant,  but tried loading csv.ijs, similar result:

    load 'c:/d/j901/addons/graphics/graphviz/testsm/csv.ijs'
|cc : child not supported: webview
: wd
|   (LF,~wd ::(''"_)'qer')    (13!:8)3
|[-22] c:\d\j901\addons\graphics\graphviz\testsm\csv.ijs

Another look for help revealed Qt Demos/webview.  Starting that results
in this message window:

[ J jqt x]
[ (I)   This demo is not supported on Win 1.8.5s/5.12.6  ]
[ [OK]        ]


So - any ideas?  Will graphviz work if webview works,  or will something 
else
be missing under Windows?
Meanwhile,  the webview demo DOES work in J807,  and so does 
...testsm/csv.ijs,
so for the time being I can play with graphviz in the older version of J.

Here are the v901 details:

    JVERSION
Engine: j901/j64avx2/windows
Release-e: commercial/2020-01-29T11:17:19
Library: 9.01.21
Qt IDE: 1.8.5s/5.12.6
Platform: Win 64
Installer: J901 install
InstallPath: c:/d/j901
Contact: www.jsoftware.com

Thanks,

Mike