Stepper Motor Library Broken

I'm on an Intel iMac and i'm using an Arduino NG, I have been trying to get the stepper motor library working but the code keeps on reseting the arduino over and over. I started commenting some of the parts out and tracked down the culprit:

myStepper.setSpeed(60);

looking at the library stepper.h and stepper.cpp, I'm still pretty stumped. If anyone can fix this library or propose a workaround, I cannot get the motor to move by itself without setting the RPMs somehow. heres the cpp code:

void Stepper::setSpeed(long whatSpeed) { this->step_delay = 60L * 1000L / this->number_of_steps / whatSpeed; }

and the stepper.h code:

// speed setter method: void setSpeed(long whatSpeed);

finally, the full library and tutorial here:

http://www.arduino.cc/en/Tutorial/Stepper

Can you post your whole sketch? In particular, what arguments are you passing to the constructor of the Stepper class (i.e. the Stepper myStepper = Stepper(....); line).