cistern can't jump platform to last valve

[lesley]

Getting frustrated and my left hand is killing me! I have TRIED for hours to jump the broken platform to get to the last valve in the corner in cistern. I got to steam valve and two other valves. I am playing on a laptop. I have to use the shift plus W key to run; with my left hand, that's two fingers pressing two keys and at the same time I have to use the space bar with my right hand to make him Jump. He does not get past ONE piece of a broken platform before falling in the water.
I am SO aggravated I was loving the game till the last couple days. Seriously, I have arthritis in my hands/wrist and this is SO hard it's ridiculous....I am not exagerrating when I say I have tried for hours.
Is there a way to avoid the last valve? It is quite clear no combination of running and jumping gets Daniel across the pieces of platform, he falls in the water and can NOT climb up the rocks. I have to make him go all the way back to stairs and start over. This is definitely the LOW point of an awesome game. It is apparent I can't go further as I can't get to the sewer without draining the water.