connect nodes with taxonomy terms fails due to lack of $node->vid

I've been trying to get wp2drupal working on my D6.12 + WP2.62 install and although tags were being ported across as Drupal terms, the "connect nodes with taxonomy terms" section wasn't doing its job. It turned out to be that this query

db_query($query, $map_postid_nodeid[$binding['object_id']], $map_postid_nodeid[$binding['object_id']], $map_catid_termid[$binding['term_taxonomy_id']]);

...requires vid not nid in the second field. To get vid I created another mapping array higher up in the code:

$map_postid_vid[$post['ID']] = $node->vid;

and then changed the query to this:

db_query($query, $map_postid_nodeid[$binding['object_id']], $map_postid_vid[$binding['object_id']], $map_catid_termid[$binding['term_taxonomy_id']]);t to be that 

...and now it works!