Thread:Project:Support desk/Notice: Undefined property: DatabaseMysql::$mTrxDoneWrites in D:\wiki\TechWiki\includes\db\Database.php on line 512

I just upgraded to MW 1.20.1 from 1.18 and now have the following error on the top of every page, and twice on the bottom.

PHP Notice: Undefined property: DatabaseMysql::$mTrxDoneWrites in includes/db/Database.php on line 512

Anyone know what might be causing it?

Product	Version MediaWiki	1.20.1 PHP		5.3.10 (cgi-fcgi) MySQL		5.5.21

-Jonathan