division by zero in node_search

Now xapian is indexing, and search is working, I'm getting a lot of division by zero errors in node_search:

This is the relevant bit of code:

  $results[] = array('link' => url('node/'. $item->sid, NULL, NULL, TRUE),
                           'type' => node_get_types('name', $node),
                           'title' => $node->title,
                           'user' => theme('username', $node),
                           'date' => $node->changed,
                           'node' => $node,
                           'extra' => $extra,
                           'score' => $item->score / $total,
                           'snippet' => search_excerpt($keys, $node->body));

Marking as active needs more info until I can track down steps to reproduce.