IndexOutOfRangeException: Array index is out of range.

Hi, can anybody help me with this? Code is without erros, but computer car in my game doesn't follow the waypoits. Here is my code:

 var waypointContainer : GameObject;
 private var waypoints : Transform[];
 private var currentWaypoint : int = 0;

 

function Start () {

            rigidbody.centerOfMass += Vector3(0, -.75, .25);
            GetWaypoints();

 } 
 
 function Update () {
 
 
     rigidbody.drag = rigidbody.velocity.magnitude / 250;
 
     NavigateTowardsWaypoint();
 
     EngineRPM = (FrontLeftWheel.rpm + FrontRightWheel.rpm)/2 * GearRatio[CurrentGear];
 
     ShiftGears();
 
     FrontLeftWheel.motorTorque = EngineTorque / GearRatio[CurrentGear] * inputTorque;
        FrontRightWheel.motorTorque = EngineTorque / GearRatio[CurrentGear] * inputTorque;
 
         
     FrontLeftWheel.steerAngle = 10 * inputSteer;
        FrontRightWheel.steerAngle = 10 * inputSteer;
 

}

function GetWaypoints () {

     var potentialWaypoints : Array = waypointContainer.GetComponentsInChildren( Transform );
        waypoints = new Array();
 
     
        for ( var potentialWaypoint : Transform in potentialWaypoints ) {
         if ( potentialWaypoint != waypointContainer.transform ) {
             waypoints[ waypoints.length ] = potentialWaypoint;
 
         }
 
     }
 
 }
 
 
 

function NavigateTowardsWaypoint () {

 var RelativeWaypointPosition : Vector3 = transform.InverseTransformPoint( Vector3( 
                                          waypoints[currentWaypoint].position.x, 
                                          transform.position.y, 
                                          waypoints[currentWaypoint].position.z ) );
 
                                                                                 
 inputSteer = RelativeWaypointPosition.x / RelativeWaypointPosition.magnitude;
 
     
 if ( Mathf.Abs( inputSteer ) < 0.5 ) {
      inputTorque = RelativeWaypointPosition.z / RelativeWaypointPosition.magnitude Mathf.Abs( inputSteer );
 

} else{ inputTorque = 0.0; }

 if ( RelativeWaypointPosition.magnitude < 20 ) {
      currentWaypoint ++;
 
         
 if ( currentWaypoint >= waypoints.length ) {
      currentWaypoint = 0;
 
         }
 
     }
 
     
 
 }