If you look at one end of the chess board (behind the pieces I think, though it may be opposite,) there is an open book which you can use to reset to the first puzzle and start the 1 to 27 steps over again. You won't get any rewards for steps you completed previously, but you should be able to continue as normal past where you're stuck. I haven't tried it. I was running out of gaming time when I had an error happen (ricochet. My fault I wasn't using a single shot weapon.) I just left and then went back in from Eris's lower area in her throne world a day or two later. If you make a mistake, at the top of the stairs around the chess board (one end or the other), there's a spot where you can undo a move, I think. I didn't use it...I saw it on one of the solution videos.