I've installed PunBB with all official extensions using PostgreSQL. There appears to be two problems with pun_approval in this setup.
1. When going to approve a message the SQL query fails. My logs so the following:
2012-05-24 03:11:58 EDT ERROR: currval of sequence "posts_id_seq" is not yet defined in this session
2012-05-24 03:11:58 EDT STATEMENT: SELECT currval('posts_id_seq')
2012-05-24 03:11:58 EDT ERROR: current transaction is aborted, commands ignored until end of transaction block
2012-05-24 03:11:58 EDT STATEMENT: SELECT COUNT(id) FROM posts WHERE topic_id=1
The debug shows the second query there and this: The error occurred on line 12 in /var/www/forum/extensions/pun_approval/functions.php
2. Clicking on a topic under unapproved topics brings up the unapproved posts page, but no posts are visible depsite it reading Posts: 1.