Try following this from a different walkthrough for the game:
Take the SHELL CASE from the area the stood on.
Click on the area to the right of the door on the left.
Drag the STONE CYLINDER from inventory into the very center of the hole. Release it when it turns gold.
Following the code on the CODED MESSAGE, rotate the dial by clicking on the two buttons on the top of the dial.
The left button is the S and the right button is D, the order in which to push is; S, D, S, S, D, S, S or Left, Right, Left, Left, Right, Left, Left.
Before entering the anti-chamber, take the STONE CYLINDER back from the slot.
And here is another walkthrough that is worded a little differently:
Use the stone cylinder on the hole near
the door at the left side of the room to open it. Open the inventory and look
at the secret message print: It contains the message SDSSDSS. This is the code
that now has to be entered, so press the left button once, right button once,
left button twice, right button once and left button twice. Get the stone
cylinder and then go left through the doorway to enter the anti chamber.
