I'm trying to open an X11 application. It yells at me that I need X11. So, I go into apps>utilities>x11 and I open it. It blinks onto my dock for about 3 seconds, then fades out, like it was quit. I've done this several times, and X11 just won't open! I've tried restarting, downloading X11 from Apple, yada yada yada, but it won't work! Can y'all help?