REDCELL -- I feel your pain!
I suspect this was an issue with the 3D engine the developers were using. And it's only an issue with the downloadable version, not the disk version, though I have no idea why.
If you look at the walkthrough, it is possible to start from a previous save where you haven't clicked on the trapdoor yet, and get through using only the number of clicks. Others have gotten through that way.
Going from left to right and clicking on each wheel:
Wheel 1 -- click 2 times
Wheel 2 -- click 13 times
Wheel 3 -- leave it just like it is
Wheel 4 -- click 15 times
Wheel 5 -- click 12 times
Wheel 6 -- click 1 time
Wheel 7 -- click 14 times
If you're correct, there's a click and you draw slightly away from the mechanism. Click on the floor near the mechanism to use the floor as an elevator.