DHCP-Problems with LiquidChrystal + Arduino Mega

I am using an Arduino Mega with the ethernet shield and lcd display. The ethernet shield is connected to the arduino using the hack described here: Arduino Ethernet Shield MEGA hack « MCUKITS

So far, everything works fine except when I try to use DHCP and the lcd display in the same Sketch (static ip and display also works).

As soon as i’m adding these two lines:

#include <LiquidCrystal.h>
LiquidCrystal lcd(32, 30, 28, 26, 24, 22);

the Dhcp.beginWithDHCP(mac) function does not seem to return any result any more :frowning:

I’m new to the arduino platform, is there anything i might have overlooked?