So i downloaded the latest version of Zenphoto and uploaded it into a new webspace with mysql etc. enabled.
But when i tried to start setup.php i just got this

So you openend http://yourdomain.com/zp-core/setup.php and got the display of the code as text? That could mean your server is not supporting PHP or it is not configured correctly. Best you contact your host about that.

somehow i doubt that it doesnt support php because i have installed wbb3.1.x on another account on the same webspace provider. i will check it anyway just to make sure

It sounds pretty weird indeed but that is the only thing that comes to mind if you get php code as text.