Meins

using System;
using System.Threading;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;

using ShowCase.Forms;

namespace ShowCase
{
    static class ShowCase
    {
        static void Main()
        {
            Application.EnableVisualStyles();

            userSettings = new UserSettings();
            //System.out.println("{0} == null = {1}", userSettings, (userSettings == null));
            if( userSettings.imagePath.Count == 0 ) // <- exception here
            {
                Application.Run( new StartUp( userSettings ) );
            }
            else
            {
                MessageBox.Show( "No Folders defined!" );
            }
        }

        static UserSettings userSettings;
    }
}