[Neos] Blank page after installation - PHP Fatal Error

[Maurice Meyer]

Hello together,

installing NEOS following the Installation guide in the documentation - yes, every step as given, I only get a blank page on loading after the installation has finished. Checking my Apache error.log, I get the following message:

PHP Fatal error:  Uncaught exception 'TYPO3\\Flow\\Package\\Exception\\PackageStatesFileNotWritableException' with message 'Flow could not update the list of installed packages because the file /path/to/installation/TYPO3-Neos/Configuration/PackageStates.php is not writable. Please, check the file system permissions and make sure that the web server can write to it.' in /path/to/installation/TYPO3-Neos/Packages/Framework/TYPO3.Flow/Classes/TYPO3/Flow/Package/PackageManager.php:946

Checking the TYPO3-Neos/Configuration/ directory, there is no file "PackageStates.php". The file permissions are set correctly, the folder belongs to the Apache executing user and has chmod drwxrwsr-x+ and is thereby writable by it. 

I'm running Apache 2.2.22 on Ubuntu 12.04 LTS with PHP 5.3.10.

Does anyone have any idea about this?