The CE walkthroughs are tested before they are released multiple times so I have to say no, Margie did not make a mistake. Are you following it step by step? Here is what MargieB says:
Zoom into the roller organ; place the ROLLER ORGAN HANDLE on the side of the roller organ.
Place the CUP WITH WATER on the small table to activate a puzzle.
Fill each cylinder to the red line using the cup of water.
Remove water from the cylinders by placing them back into the cup.
Fill cylinder A with CUP OF WATER and pour it into cylinder C.
Place the remainder of cylinder A into cylinder B.
Empty cylinder C.
Repeat those steps twice to completely fill cylinder B.
Fill cylinder A with CUP OF WATER.
Pour cylinder A into cylinder C.
Empty cylinder C test.
Place the rest of cylinder A into cylinder C.
Fill cylinder A and pour it into cylinder C to complete the puzzle.
Place the ROLLER ORGAN PART into the compartment below after the puzzle has been solved.
Turn the handle; pick up the PAPER CLIP and HANDKERCHIEF on the letter.