another way thats a bit more direct but probably a little bit less reliable in terms of skidding:
Code:
motor[FL] = power;
motor[FR] = power;
motor[BL] = power;
motor[BR] = power;
while(nMotorEncoder[FL] < units){}
Stop(); // we wrote this function to set every motor to 0.
please note that this code is for a four wheel drive robot.