Thread:Project:Support desk/update.php fatal error

MediaWiki 1.16.0 PHP 5.2.15 (cgi-fcgi) MySQL 5.1.53-log

I'm trying to install the LiquidThreads extension and need to run the update.php script to update the database. However, when I tried to run it I got the following error:

Fatal Error: Call to a member function getDbType on a non-object in /home/[username]/[host]/w/maintenance/doMaintenance.php on line 79

I have the following extensions installed:
 * Semantic Mediawiki
 * Admin Links
 * ParserFunctions
 * CategoryWatch
 * CreatePage
 * MooTools12Core
 * MultiBoilerplate
 * WYSIWYG Extension

Any ideas?