I'll implement your code next thing tomorrow. However, it might be something else. I am powering the whole setup with a switchable power supply (1500mAh) set at 9 volt. Just now I read in a post that the voltage regulator can't handle this amount and will overheat and lock up the board. I'll try to switch the power supply to 7,5 volt and see what happens.
My question to you guys: How do you power your Duomilanove - ethernetshield setup?