I have read this post and also this other:
I have a problem with the "2A motor driver" from DFROBOT:
and the libelium XBee shield:
I can insert/plug the 2A motor driver on my Arduino UNO board as the first shield in the stack. And then I put the XBee shield (with a WiFly module) on the top of the stack.
Because of libelium XBee shield needs Vcc(5V) and GND from the ICSP header and the 2A motor driver does not provide this ICSP pins, I route a pair of wires from this shield to the XBee shield with these power lines (5V and GND). So, it seems to work because I see leds of all shields blinking in some manner. But the program does not work because WiFly module cant't communicate with my PC and can't get DHCP IP, etc. On the other hand, if I plug the XBee shield+WiFly module directly on the Arduino board as the unique shield on the stack (without plugging the 2A motor driver), the set works properly communicating with my PC.
So I can't find wheres's the problem with the motor driver. I read the schematics/manuals and these shields seem not to haven common pins or signals....
Is there anybody who can help. Thank you very much in advance.