A few things to try because the game was a rushed job and the slate can be very "buggy" at times.
1- Save your game at that spot and come back through the saved game.
2- Or go to a previous save and start aknew from there.
3- One other possibility is that you have not activated one of the power consoles.
Btw, if you could give some extra infos about your drawing for that puzzle it might help us to guess what the problem could be. (like a wrong drawing or a baddly done drawing...not the right proportions) or even backing off on the wrong side like at the tram where you have to be inside the gondola while the Bahro is supposed to do his "job".