@kraigg: Check out the “View” link under one of your forums in WordPress Admin > Forums. Note that using the “View” link works; the difference between this URL and the one linked from /groups-shortcode/ is that the one that works ends in ‘forum’; the link from /groups-shortcode/ ends in ‘forums’.
In short: forums are there, but not where /groups-shortcode/ expects to find them. It looks like you have some sort of URL forwarding turned on so that when visiting a group, the first tab opened is the forum tab. However, it is should point to /forum/, not /forums/.
