Shouldn't I be able to castle here(Fischer Random)

According to the castling rules for Fischer Random chess I'm pretty sure I should be able to castle in this situation as black, and end up with the king remaining where it is and the rook to the left of the king on C8. I'm sure i saw the exact same situation(with regard to the king and rook) in a Magnus Carlson game on YouTube the other day so I'm not sure what I'm doing wrong.

Shouldn't this be a valid move here? I've not moved either piece in this game yet. Here's the screenshot,

http://imgur.com/gallery/cSIaVia

Thanks for your help.

I think that you can't play a move because it is long castle and the king should go to c1 and rook to d1.

Oh, yeah. I see it now. I've learnt something new today anyway. Thanks very much.

mat yok