MySQL error when clicking 'email subscription'

I have the latest CVS version of og and og-related modules and the latest CVS versions of Drupal.

When a user who is a member of a group clicks the 'email subscription' link in the Group notifications block, they receive the following MySQL errors:

Warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1 query: SELECT COUNT(*) FROM og og INNER JOIN node n ON og.nid = n.nid INNER JOIN node_revisions r ON r.vid = n.vid INNER JOIN users u ON n.uid = u.uid INNER JOIN og_uid ou ON ou.uid = u.uid INNER JOIN node_access na ON na.nid = og.nid WHERE (na.grant_view >= 1 AND ((na.gid = 0 AND na.realm = 'all') OR (na.gid = 0 AND na.realm = 'og_public') OR (na.gid = 0 AND na.realm = 'og_all'))) AND og.nid IN () in /var/www/includes/database.mysql.inc on line 120

Warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ORDER BY n.nid DESC LIMIT 0, 50' at line 1 query: SELECT DISTINCT(og.nid), n.title, r.body, n.uid, u.name, og.description FROM og og INNER JOIN node n ON og.nid = n.nid INNER JOIN node_revisions r ON r.vid = n.vid INNER JOIN users u ON n.uid = u.uid INNER JOIN og_uid ou ON ou.uid = u.uid INNER JOIN node_access na ON na.nid = og.nid WHERE (na.grant_view >= 1 AND ((na.gid = 0 AND na.realm = 'all') OR (na.gid = 0 AND na.realm = 'og_public') OR (na.gid = 0 AND na.realm = 'og_all'))) AND og.nid IN () ORDER BY n.nid DESC LIMIT 0, 50 in /var/www/includes/database.mysql.inc on line 120

There are no other node access modules installed - I did have TAC installed but no longer need it due to the increasing functionality available in og and have removed it, reset the node_access table and reinstalled og.

This error continues to appear.

Any ideas anyone?