Processing+OpenCV - FaceDetection on a Movie

I am using Processing with the OpenCV Lib and wanted to rewrite the example Code from the creators Git so that instead of doing Face Detection on a Camera Capture I'll load a video (.mp4).

Link to the Git and the example Code (which is working): Link

Here is my Sketch:

import processing.video.*;
import gab.opencv.*;
import java.awt.Rectangle;

OpenCV opencv;
Movie myMovie;
Rectangle[] faces;

void setup() {
  size(480, 270);

  myMovie = new Movie(this, "people3.mp4");
  myMovie.loop();
  opencv = new OpenCV(this, myMovie.width, myMovie.height);
  opencv.loadCascade(OpenCV.CASCADE_FRONTALFACE);
}

void movieEvent(Movie myMovie) {
  myMovie.read();
}

void draw() {

  background(0);
  if (myMovie.available()) {

    opencv.loadImage(myMovie);
    faces = opencv.detect();
    image(myMovie, 0, 0);

    if (faces != null) {
      for (int i = 0; i < faces.length; i++) {
        strokeWeight(2);
        stroke(255, 0, 0);
        noFill();
        rect(faces[i].x, faces[i].y, faces[i].width, faces[i].height);
      }
    }
  }
}

What I'm getting is an IndexOutOfBoundsException: Index: 3, Size: 0 at openCV.loadImage(myMovie) and I don't know why.

Appreciating any help! :-)