Bootcamp-partition doesn't show up in startvolume-selection,cant be used in Parallels

I've got a 10.8.4 machine with the latest Paralells installed. I'm using my Bootcamp-partition (Windows 7) in Paralells as a virtual machine.

This works very good.

I'd like to do the same with my work-iMac however Paralells doesn't recognize the Bootcamp-partition.

After some investigation I found out it has to appear as a startvolume under System Settings. For some reasons on my work-iMac there is no Bootcamp-partition in the window anymore. The Bootcamp-partition is perfectly useable by launching it via the OS selection (hold option-key after start).

Here's a screenshot of how the startvolume selection is supposed to look:



This is how it actually looks:

http://i.stack.imgur.com/f4Uk0.jpg