There is an error. Please report the message and full backtrace in the Piwik forums.
Notice: Undefined property: Piwik_CoreUpdater_Controller::$pathRootExtractedPiwik in /var/lib/piwik/plugins/CoreUpdater/Controller.php on line 99
#0 Piwik_ErrorHandler(8, Undefined property: Piwik_CoreUpdater_Controller::$pathRootExtractedPiwik, /var/lib/piwik/plugins/CoreUpdater/Controller.php, 99, Array ()) called at [Piwik_CoreUpdater_Controller->oneClick_Unpack() called at [/var/lib/piwik/plugins/CoreUpdater/Controller.php:63](/var/lib/piwik/plugins/CoreUpdater/Controller.php:99]#1)#2 Piwik_CoreUpdater_Controller->oneClickUpdate()#3 call_user_func_array(Array ([=> Piwik_CoreUpdater_Controller Object ( => ,[=> Array (), => Array (),[=> Array (), => CoreUpdater,[=> , => ,[=> 0, => Piwik_Site Object ([=> 0),newVersion => 1.2.1,[=> /var/lib/piwik/tmp/latest/latest.zip),1 => oneClickUpdate), Array ()) called at [Piwik_FrontController->dispatch() called at [/var/lib/piwik/index.php:57](/var/lib/piwik/core/FrontController.php:125]#4)
please SEARCH before opening a ticket, this has been reported in the forums a few times and in here already... thanks