include "stdafx.h"

#include "opencv2/objdetect.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"

#include <iostream>
#include <stdio.h>

using namespace std;
using namespace cv;

/** Function Headers */

/** Global Variables */
String face_cascade_dir = "haarcascade_frontalface_default.xml";
CascadeClassifier face_cascade;

int main(void)
{
    // --1: Load Cascades.
    if (!face_cascade.load(face_cascade_dir))
    {
        printf("(!)Error loading cascade.\n");
        system("pause");
        return -1;
    }

    // --2: Load Image.
    Mat image = imread("rosto_frontal.jpg",CV_LOAD_IMAGE_UNCHANGED);
    if (image.data == NULL)
    {
        printf("(!)Error while loading image file.\n");
        system("pause");
        return -1;
    }

    namedWindow("Loaded Image", CV_WINDOW_AUTOSIZE);
    imshow("Loaded Image", image);

    // --3: Preproccess Image.
    Mat gray;
    cvtColor(image, gray, COLOR_BGR2GRAY);
    equalizeHist(gray, gray);
    resize(gray, gray, Size(800,640), 0, 0);

    namedWindow("Proccessed Image", CV_WINDOW_AUTOSIZE);
    imshow("Processed Image", gray);

    // --4: Apply Classifier.
    vector<Rect> faces;
    face_cascade.detectMultiScale(gray, faces, 1.1, 3, CASCADE_SCALE_IMAGE, Size(60, 60));

    system("pause");
    destroyAllWindows();

    return 0;
}

Ok. There is my code. It runs fine until it reaches the detectMultiScale function and crash. I get the following message in the application console:

OpenCV Error: Assertion failed (!std::numeric_limits<_Tp>::is_integer || width == 0 || result / width == height) in cv::Rect_<int>::area, file C:\build\master_winpack-build-win64-vc14\opencv\modules\core\include\opencv2/core/types.hpp, line 1751

I've searched everywhere for an awnser. Couldnt find one. Any help would be appreciated. Thank you.

Edit: I am using OpenCV 3.3