I've got WP 3.2.1 & BP 1.5.1. Installed and activated the Membership plugin and made the change in the line 23 of membership/membershipincludes/includes/membership-config.php (which to me is a weird step). As admin, I don't see the menus that I'm supposed to see. For instance, I don't see Membership -> Edit Levels. I attach a snapshot.