Problem registering custom taxonomy

You haven’t passed the labels to register_taxonomy() correctly. That function works the same as register_post_type(), and you need to pass the labels the same way: as part of a 'labels' array in the arguments.

Please refer to the documentation for the full list of accepted labels, but essentially, you need to organise the arguments this way:

$loc_args = array( 
    'hierarchical' => true,
    'labels'       => array(
        'name'          => 'Locations', 
        'singular_name' => 'Location', 
    ),
);

register_taxonomy( 'locations', array( 'member' ), $loc_args );

That’s only 2 of the labels though. You will need to provide the full list so that “Category” does not appear anywhere.