I installed this plugin and I do not have any BP Groups Extras under my Settings menu as explained in the Installation instructions.
I have no idea how to try and troubleshoot this :/
I tried deactivating and reactivating the plugin several times with no luck, and switching to the default theme.
I tried going to http://cmha-dev.rtraction.com/wp-admin/options-general.php?page=bp-groups-extras (just a guess!) but it did not work.