Riva,
I uploaded your ScrollTest4 code....
This is the run in I'm having with my mega2560.....
so for this one I have the Duemilanove running....
but the text is scrolling vertical and the letters are backwards.....
man this is so frustrating..
I'm just using 1 max7219 and 1 matrix right now......
I wire my components up via this site:
http://www.pjrc.com/teensy/td_libs_Matrix.html
My matrices say XH-1088BRW on them as well......