marlin & HBP (no replies)

hello guys,
i'm tryin' to build my first reprap.

i've a arduino 2650rev3 + ramps 1.4 with lcd & support shield (www.gadgets3d.com)

i've hacked a ATX power supply to power the ramps, arduino is powered by usb cable.

now this is my question:
i've downloaded the Marlin Firmware from here : [github.com]
i've changed some parameters in configuration.h and some others for lcd and sd

loaded on arduino, but when is connected to pronterface hbp doesn't turn on.

(with sprinter firmware hbp turn on normally, but with this firmware i can't use my lcd and sd)

any ideas?

thanks!