quotes evaluation in wikitools.admin.inc

This is what I got when accessing http://www.example.com/admin/settings/wikitools, running Drupal-6.14 on PostgreSQL:

• warning: pg_query() [function.pg-query]: Query failed: ERROR: column "_" does not exist LINE 1: ... n1, node n2 WHERE LOWER(REPLACE(n1.title, "_", " "))... ^ in /home/example.com/htdocs/includes/database.pgsql.inc on line 139.
• user warning: query: SELECT COUNT(DISTINCT(n1.nid)) FROM node n1, node n2 WHERE LOWER(REPLACE(n1.title, "_", " ")) = LOWER(REPLACE(n2.title, "_", " ")) AND n1.nid != n2.nid AND n1.type IN('blog','image') AND n2.type IN('blog','image') in /home/example.com/htdocs/sites/all/modules/wikitools/wikitools.admin.inc on line 17.

I'm attaching a patch the quality of which I have absolutely no idea. It looks like working.