Cubase 5 - Middle C (C3) moves to C4... WHY?

Hello, I totally newbie here, so : hello to everyone.

I just registered here, because I have a problem…

During working with my Cubase 5, middle C of my VirusTI just moved octave down.
So, when I push middle C on the keyboard (C3) I see pushed C4 on Cubase’ keyboard on the screen.

Settings of my VirusTI is ok…

Any idea how to resole it?