hope I have
goooood news for u2 mtif
I spend few hours trying, and now finished testing 5 min ago, and yep IT WORK'S for me, forum appears in GJ Config, and there is no errors in tools, moreover GJ forums work from frontend with no problems!
solution: (but only if you are SURE that YOU HAVE 1.6 Kunena Forum, and GJ 2.2)
in file /components/com_comprofiler/plugin/user/plug_cbgroupjive/plugins/cbgroupjiveforums/cbgroupjiveforums.php
about line 110 (after this ->): $model->detected = CBTxt::T( 'Kunena 1.6' );
add line:
require_once( $path . '/components/com_comprofiler/plugin/user/plug_cbgroupjive/plugins/cbgroupjiveforums/models/kunena16.php' );
thats all

hope it will work for u2
...
and info for devs:
PS.1 Im not php programer, so I dont know Is this elegant or best solution - for sure not.

It was only my logical searching and trying. Then Sorry if its something wrong with this my code, but its really works for me.
PS.2 My condition was: I know for sure that I have Kunena 1.6.3, and api file exist, so mayby problem is with that class cbgjforumsModel because it is not read form kunena16.php file as it should be read?
so first I copied all code from kunena16.php file (from 3x this $_PLUGINS->registerFunction... to the end) and placed it after $_PLUGINS->registerFunction... block in cbgroupjiveforums.php file.
And it started works! In GJ Config forum was detected and existed Kunena categories was displaed for selection.
so my next condition was that maybe this:
$model->file = $plugin->absPath . '/plugins/cbgroupjiveforums/models/kunena16.php';
do not work - for example because of my server environment or config?
so I read in "php help" what is this "require_once" function you use for read com_kunena/api.php file few lines above - and adopted it (in my opinion

of course) to force read this kunena16.php
and it started work!!! I don't know why but it is.
PS.3 if I "//" this original 108. line: $model->file = $plugin->absPath . '/plugins/cbgroupjiveforums/models/kunena16.php'; - its still works ok, so Am I wrong that there was problem for me?
PS.4 Thanks for GJ btw, great plugin!
best regards!