Error in C# "the type initializer for 'emgu.cv.cvinvoke' threw an exception."

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using Emgu.CV.UI;

         
namespace WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        Capture capturecam = null;       //instance for capture using webcam
            bool CapturingProcess = false;   //boolean stating the capturing process status
            Image<Bgr, Byte> imgOrg;   //image type RGB (or Bgr as we say in Open CV)
            Image<Gray, Byte> imgProc; //processed image will be grayscale so a gray image
            
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

            
            try
            {
                capturecam = new Capture();
               
            }
            catch (NullReferenceException exception)
            {
                MessageBox.Show(exception.Message);
                return;
            }
            Application.Idle += new EventHandler(ProcessFunction);
            CapturingProcess = true;

        }
        void ProcessFunction (object sender, EventArgs e)
        {
            imgOrg=capturecam.QueryFrame();
            if (imgOrg == null) return;

            imgProc = imgOrg.InRange(new Bgr(50,50,50) , new Bgr (255,255,255));
            imgProc = imgProc.SmoothGaussian(9);
            original.Image=imgOrg;
            processed.Image=imgProc;
        }

        private void playorpause_Click(object sender, EventArgs e)
        {
            if (CapturingProcess == true)
            {
                Application.Idle -= ProcessFunction;
                CapturingProcess = false;
                playorpause.Text= "Play";
            }
            else
            {
                Application.Idle += ProcessFunction;
                CapturingProcess = true;
                playorpause.Text= "Pause";
            }
        }
    }
}

"The type initializer for 'Emgu.CV.CvInvoke' threw an exception."