Arduino Mega Problem with MidiVOX

Hello guys.
I bought a MidiVOX Shield for my project. As i tried it with my first Arduino Mega it didnt work. So i replaced all parts of the shield. Still not working. So i ordered a Arduino Duemillanove. It works with that.
So i thought, hey maybe only your first Mega is broken.
So i ordered another Mega.
And it just doesnt work on the Mega.
The Problem is with receiving Midi Data via RX.
Anyone got a hint how to get it to work ?
Here is the link to the shields code and specs: http://www.narbotic.com/kits/midivox/

I cant finish my project because of that mess. Please help a poor guy who spent all his money on something that he doesnt get to work :-[

Greets from Austria