Blocking author paging for blog entries?

You can send any request for author pages to a 404 with a simple action on parse_query.

add_action( 'parse_query', '_404_author_archives' );
function _404_author_archives( $qr ) {
    if( is_author() )
        $qr->set_404();
}

That should send any requests for an author page to a 404.

If you wanted to go a bit further and remove the author rewrite rules you could also do that quite easily with a filter on author_rewrite_rules.

add_filter( 'author_rewrite_rules', 'remove_author_rules' );
function remove_author_rules() {
    return array();
}

Untested, but you’ll have to let me know if that’s not quite enough author elimination..