Stepper Motor not Stepping Properly
Ok so I'm not familiar with the sheild or API (or motor lol) but going off the spec sheets etc 

Leave the red wire disconnected [see 1] and try this code and report back what happens:

  #include &lt;Wire.h&gt;
  #include &lt;Adafruit_MotorShield.h&gt;
  #include "utility/Adafruit_MS_PWMServoDriver.h"

  Adafruit_MotorShield AFMS = Adafruit_MotorShield(); 
  Adafruit_StepperMotor *myMotor = AFMS.getStepper(64, 2); // 64 steps pr revolution
                                                           // Using M3 and M4 of shield

  void setup() 
  {
    AFMS.begin();  // create with the default frequency 1.6KHz
    myMotor-&gt;setSpeed(30);  // 30 rpm, so 1 full turn every 2sec  
  }

  void loop() 
  {  
    // 64 steps per motor shaft revolution,
    // 64 revolutions of motor per output shaft revolution
    myMotor-&gt;step(4096, FORWARD, DOUBLE);    // Should be 1 rev in one direction
    myMotor-&gt;step(4096, BACKWARD, DOUBLE);   // and 1 rev in other direction
  }


[1] : your motor is unipolar (wikipedia on unipolar and bipolar motors), according to its documentation. The red wire is the central tap, and useless in this context.