[FLOW3-general] @var annotation seems to be invalid

[Heiko Kromm | Paints]

Hi List, 

I have a fresh FLOW3 1.0 installation and tried to install a package I created on an earlier version. 
After changing a lot of annotations I'm stuck on this error message: 

Uncaught Exception The @var annotation for "...\Domain\Model\Admin\Vat::$title" seems to be invalid 

There is only a simple declaration an string at this position: 
class Vat { 

/** 
* Vat Title 
* 
* @var string 
*/ 
protected $title = ''; 


I found the installation hints in the wiki, but it only describes how to prevent this error on Windows. But my installation is on ubuntu linux. 
Any hints on that? 

Regards 
Heiko