The "ScalingFunctions" in red means that it is an unknown option. You may be using a different version of Mathematica than Mr. Huisman is using. To determine your version use:`
$Version
As you can see the function "ScalingFunctions" is in red and I do not know if this could cause the program to fail.
Thank you very much for your help and time. I try to do what you suggest and it works for me, but not with all the code. It seems to me this way.
Try this:
Plot[Sin[x], {x, -3, 3}, ScalingFunctions -> {"Reverse", Automatic}]
