Organic Groups - admin unable to reassign a user's group subscriptions

OK, I am going to do the best I can to describe the issue I am experiencing.

By way of background: I am pulling together a website for our Cub Scout Pack. Since we’re a fairly large pack and have 11 dens, I thought I would use Organic Groups and allow each den to have their own area on the site. I have also implemented the Groups (dens) as Private Groups because not everyone in the Pack is tech savvy and this allows me limit the information they see to their den and the Pack information - in short, it reduces the apparent complexity of the site...

So, I am able to see the individual groups when I create a user. No problem. Works well.

My problem is that I cannot edit which group's a user is subscribed to once their profile has been created.

In short, even as THE administrator, I am not able to change a user’s group subscriptions...

Any ideas? Am feeling pretty dim here...

Thanks,

Steven