I found a tutorial for parallax scrolling, and i have code, but i have a new problem.

[Simpson55]

You have to give more information about your code.
Did you define background[0] and background[1] in the room editor or in the code?
You should also make sure that both backgrounds are set to "repeated".
As for the speed, you can tweak the 0.4 and 0.6 constants until it looks about right. The lower the constant is, the faster the scrolling will be.