So I just spent an hour debugging an issue when you try to activate the plugin:
Plugin could not be activated because it triggered a fatal error.
Could not create the required column. Please enable debugging for more details.
And when you enable bugging you get this error:
Notice: Trying to get property of non-object in */wp-content/plugins/bp-group-hierarchy/index.php on line 40
So after a lot of debugging I figured out the problem was simply that you need to enable buddypress groups in settings -> buddypress for this plugin to work!
Anyways... even though this is a silly error it's easy to make if you have been messing around with settings before installing. Hopefully this saves someone some time!