Where did they go?

I have burned 2 dvds on my Mac Pro with the superdrive. I used the burn folder I created and left on my desktop to export 1,500 jpegs to. Burned the dvd, and when it was done, the title showed up on the disc on my desktop with its own new icon, and said it was successful. I looked in the disc and saw the images on it and was content. Ejected and stored for later. Now I am trying to open it, and my Mac Pro is acting like it is a blank dvd? Any*help is greatly appreciated.