Mega 2560 with Ethernet and Motor Shield crashes

Ipad app is controlling four independent small motors.

We are able to use OSC to send messages (motor Speed ints) over wifi, but the arduino crashes almost right away (3-5 commands). The arduino is able to run four motors no problem, but the program still crashes with only one motor hooked up. I have attached the code and hopefully someone smarter than me can explain what is going on.

Please help

Cheers,
Simon

OSC_Laser_Controller_1.ino (7.41 KB)