Re: fatal error: members and groups.
If you are seeing “Call to undefined function bp_search_form_action()” then you are mixing trunk files up with beta 1 files.
You cannot use the beta 1 themes with the trunk plugins. If you’re going to update your BuddyPress installation with the trunk, you need to make sure the themes are the trunk versions too.
There are still last minute changes going into the themes until 1.0 final.