MissingMethodException: Method not found: 'UnityEngine.Random.Range'. Boo.Lang.Runtime.DynamicDispatching.MethodDispatcherFactory.ProduceExtensionDispatcher ()

var speedMin;
var speedMax;
var radiusMin;
var radiusMax;

function Update () {
    direction = Random.onUnitSphere;
    direction.z = 0;

    var speed:int = Random.Range(speedMin, speedMax);
    var radius:float = Random.Range(radiusMin, radiusMax);

    centerPoint = direction * radius + transform.position;
}

[Edit by Berenger : Code formatting]