This can be fixed by using single quotes - it's all the same to mysql.

* warning: pg_query() [function.pg-query]: Query failed: ERROR: column "term" does not exist LINE 1: DELETE FROM page_title WHERE type = "term" AND id = 2 ^ in /web/vhosts/drupal-6.14/includes/database.pgsql.inc on line 139.
* user warning: query: DELETE FROM page_title WHERE type = "term" AND id = 2 in /web/vhosts/drupal-6.14/sites/all/modules/page_title/page_title.module on line 252.