Thanks for the input royboy,
I had already changed the parameters, but its good to see them from you too.
I don´t see the numbers in the application screen, but I have add some print statements in the Processing code and now they are there. (I´m learning quick, after all its works almost the same as the Arduino code 
)
The average color in the little screen however did work, that´s why I assume that it has to do with the Arduino - RGB Led combination.
When I bypass the average colour and feed the Arduino with zero's for all colours then the LED stays off, but when I increase the value to 1 then it´s lightning up.
I use the same pins as you did and I don´t use the driver yet, just a plain RGB led with resistors to the Arduino.
But I´m sure that I will find the problem, and more sure that its not in your code.
The part in your code :
r = r+(int)(255&(pixel>>16)); //add up reds
g = g+(int)(255&(pixel>>8)); //add up greens
b = b+(int)(255&(pixel)); //add up blues
is something i have to discover how it works because the are so many shades of red (and blue and green)
Just playing and discovering now, that's also a fun part for me.