I realize that many users are frustrated here. Okay, in my case the update has not worked. I examined my environment and noticed that even during the upgrade jUpgrade doesn't create a new database schema. All other queries will fail. My solution: Joomla 2.5 installed manually in /jupgrade. In jUpgrade skip checks, skip download, skip install. The following update statements will work and the Joomla update is still successful. Hope this helps.