Hi,
I am a bit confused, I am running this package on a clean project in Unity 4.2 and there is no Joystick.cs in that package actually. Can you try on a fresh project again?
else, what package did you install as well? I believe joystick is a unity script, so maybe you need to update your packages if you moved from a 3x project to a 4x project.
bye,
Jean