problem with sdl_flip()

Okay so ive been through lazy foos tutorial.. now im attempting to make a pong game, but now SDL_flip is giving me a problem.. when I comment it out my code runs fine.. I get a return 3.

Code:

#include <string>
#include "SDL\SDL.h"
#include "system.h"
#include "Image.h"

#define BPP 32
#define SCREEN_W 640
#define SCREEN_H 320

SDL_Surface* display = NULL;
int main(int argc, char* args[])
{
    System system(SCREEN_W, SCREEN_H, BPP, "Pong");
    system.init();
    Image image;
    SDL_Surface *message;
    message = image.loadBMPImage("");
    image.applySurface(0, 0, message, system.screen);
    SDL_Flip(display);
    SDL_Delay(2000);
    system.cleanUp();
}

This is probably better off on SDL's mailing list but I'll see if I can help.

The problem here is you're not showing how you initialize SDL. What surface parameters are you setting when you set the display mode?

If you're having a problem when SDL_flip() is being called and not when it's commented out, you probably didn't set your screen mode to include SDL_DOUBLEBUF.

I assume you create the screen mode in your system class so check that first.

You didn't init SDL?

possibly im not sure. I decided to move on from this and I did it in another project and everything works fine