with og access, img_assist gives: Fatal error: Unknown column 'n.nid' in 'on clause' query:

When I apply organic group's og access, i get the following error on the front page of my site _only_ when img_assist is enabled. I don't get this error if I go to other parts of the site... very wierd!

Fatal error: Unknown column 'n.nid' in 'on clause' query: SELECT DISTINCT(n.nid), n.title, n.body, f.* FROM files f INNER JOIN node_access na ON na.nid = n.nid , node n WHERE (na.grant_view >= 1 AND CONCAT(na.realm, na.gid) IN ('all0','og_public0','og_all0')) AND f.nid = n.nid AND f.fid = 7 in /home/.haywire/gourd/masha.barashek.org/includes/database.mysql.inc on line 66

I'm using drupal 4.6.6;

I appreciate any help.

charles