Need help to interface the arduino and SMC01A

Please I need help to interface the Pololu Serial motor controller this one http://www.pololu.com/products/pololu/0101/ , I have try everything .

Thanks.

OK this is what i have :

// Arbot v1.0 (dist 90 - 400)
byte derF[] = {128,0,5,50};
byte izqF[] = {128,0,7,50};
byte derB[] = {128,0,4,50};
byte izqB[] = {128,0,6,50};

int dist;
byte lop,lopp;
byte reset = 8;

void setup() 
{ 
  Serial.begin(9600);
  pinMode(reset,OUTPUT);
  digitalWrite(reset,HIGH);
  delay(1000);
}

void giraDer()
{
  for (lop=0; lop<4; lop++)
  {
    Serial.print(izqF[lop]);
  }
  delay(20);
  for (lop=0; lop<4; lop++)
  {
    Serial.print(derB[lop]);
  }
  delay(20);
}

void giraIzq()
{
  for (lop=0; lop<4; lop++)
  {
    Serial.print(derF[lop]);
  }
  delay(20);
  for (lop=0; lop<4; lop++)
  {
    Serial.print(izqB[lop]);
  }
  delay(20);
}

void forward(byte vel)
{
  for (lopp=0; lopp<3; lopp++)
  {
    Serial.print(derF[lopp]);
  }
  Serial.print(vel);
  delay(20);
  for (lopp=0; lopp<3; lopp++)
  {
    Serial.print(izqF[lopp]);
  }
  Serial.print(vel);
  delay(20);
}

void backward(byte vel)
{
 for (lopp=0; lopp<3; lopp++)
  {
    Serial.print(derB[lopp]);
  }
  Serial.print(vel);
  delay(20);
  for (lopp=0; lopp<3; lopp++)
  {
    Serial.print(izqB[lopp]);
  }
  Serial.print(vel);
  delay(20);
}

int distancia()
{
  int dist;
  dist = analogRead(0);
  return(dist);
  delay(53);
}

void loop() //this is just for test
{
  forward(127);   //goes forward 10 sec
  delay(10000);
  for (byte vel=127; vel>19; vel--) // then slows down
  {
    forward(vel);
  }
  delay(10000);
  forward(0);  //brakes
  delay(5000);
  giraDer(); // an then turn to right
  delay(5000);
}

Try byte derF = {128,0,3,50};

That should drive the first motor forwards if I read correctly.

3 days ago I discover it was in ONE motor mode, working fine.

Thanks.