when i go up a stair case the screen stays black i can only see my mouse courser and i think i hear foot steps...

I did not experience this bug... does it happen with all stairs, or only specific ones? What about going DOWN stairs? Also you can try submitting a support request to GOG about it to see if they know what might be causing it.

Sounds wierd, never happend to me nether. What floor are you on?

down is ok the first stair case you go down in the game worked fine but now i cant go up the stairs to progress to the next part of the game..and i tried the NE stairs..no go and sw stairs and it just turns black =/

What OS do you have? If it is Vista or Win 7 sett the game launcher to start as admin.

Never happened here either. I have no answer, but the only thing that comes to mind I wonder about is if you are running on a desktop or laptop and what graphics card you running.
Also, are all your drivers up to date?
I hope you figure it out to be able to play this gem of a game.