I have tried the screenshot, and after uploading I get an error but that could be due to my connection. Anyway I'm going to upload the error report to x-fire.
Odd: I looked through the error report, and is not showing an error code of any kind which would help with determining the problem.
So, the screenshot itself does work while playing the game if that is what you were more interested in.

I'll post future info on the x-fire forum area.
Cheers..