In the Oscar winning short Film "Black-Driver", there are two main characters. An old Lady and young man. But who of them is the Protagonist and who is the Antagonist? I read somewhere that it's the old woman but with no explanation why...

You can watch the full 12min shortfilm here f.e.:

http://www.youtube.com/watch?v=wiuv5hzj5i4

I read somewhere that it's the old woman but with no explanation why...
You read that the old woman is which one?
*I'm kinda feeling like a bit of advertising is trying to be done...hmmm*

Haha. Yeah I'm advertising for a twenty year old short film which is available on YouTube.

Ha! You never know! ;) I did not go to your link, but looked up short films that had won awards, I think maybe the film you're referring to is Schwarzfahrer ('Black Rider'), not Black Driver?
Schwarzfahrer - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Schwarzfahrer)

But who of them is the Protagonist and who is the Antagonist? I read somewhere that it's the old woman but with no explanation why...
You read that the old lady was which one? The protagonist or antagonist?

Yeah, exactly "Black Rider". I'm sorry.

I read that the old Lady is the Protagonist. Although she is the bad Person. That's OK, the protagonist doesn't have to be good but in descriptions about how to identify the protagonist, one criteria is f.e. "you can identify yourself with protagonist". Which is not really given in the movie in my opinion.