Undefined variable: optionalUserInfo after Update to 2.0.1


Hi, after I updated to 2.0.1 I got the following error:

There is an error. Please report the message (Piwik 2.0.1) and full backtrace in the Piwik forums (please do a Search first as it might have been reported already!).

Notice: Undefined variable: optionalUserInfo in /www/sbg/tracking/htdocs/core/Filechecks.php on line 97 

Backtrace -->

#0 Piwik\Error::errorHandler(...) called at [/www/sbg/tracking/htdocs/core/Filechecks.php:97]
#1 Piwik\Filechecks::dieIfDirectoriesNotWritable(...) called at [/www/sbg/tracking/htdocs/core/FrontController.php:307]
#2 Piwik\FrontController->init(...) called at [/www/sbg/tracking/htdocs/index.php:70]

Follwing trooubleshout I tried:
Removed all Files from installation, copied all Files from latest.zip to the folder and tried to access the server. but nothing!


I found the error by my self.
I needed to change the owner for the installation. Original the manual says I have to use www-data:www-data but my permissions are :www-data


Thank you! This solved my problem after upgrading to 2.2.1.