Problem with virtual drive

Hello,

I'm not a mac user for very long. Since june I have installed Parallels 7 and Windows Vista. I didn't use it for maybe the last 2-3 weeks, today it doesn't work. I get the following german message:

Translated that might be something like

As I wrote: I am not a mac user for very long, so I'm not familiar with the deeper secrets of the OS like it was maybe in Windows. Till today I never had much problems. I also changed nothing but installing the updates. But after the "big" update to mountain lion, everything worked well.

What did I do:
I checked the permissions to this path. In my system the finder using german wording. But my user has the permissions for read and write in the whole directory.

Does anybody have an idea what I can try to do?