App usability questions

[nolan_d bigfoot com (Nolan J. Darilek)]

I think I've solved my navigation issues; I dug up an old message
containing the URL for the gnome 2.2 accessibility book, and read that
more closely. I did have another issue, though, and while it isn't
entirely gnopernicus-related, maybe a bit of anecdotal usability stuff
will prove useful to someone. :)

I'm trying to run jack-rack, available from
http://pkl.net/~node/jack-rack.html. Navigation works well with
gnopernicus. I can open and navigate menus, move around the plugin
configuration dialog, etc. Unfortunately, however, I can't seem to
enable a plugin. As jack-rack is at version 1.4.something, I'm
thinking that it's functioning fine, and the problem lies with me not
understanding the interface. There are also several buttons, but when
I tab over them I'm merely told that they're "pushbuttons" and no
label is read. I'm wondering if these might be ok/apply/cancel
buttons, if they're graphics and not labeled, etc.

Would anyone mind giving this app a glance and telling me what I may
be missing? I feel as if gnopernicus is very close to meeting my basic
needs, even in its early stages; I just don't quite know how to
accomplish the minor task of navigating this one UI element. :)