Buddypress Social Theme's group is faulty. When click on group link, users see Group Left Widget and it tells to add widget, but the link is not redirect to the widget section or anything like that, but it redirect users to wpmu dashboard. Also how you add widget to group anyway? The same thing goes with Group Right Widget.
Also, when create group, the part where to crop group avatar seems a little faulty, because when finishing cropping avatar, the avatar was not shown until group done created and click on the group after the group creation. Also the very last step which is to invite other users to join group is not working, so I have to click next to finish group creation.