Sony DVD Recorder

I had some home video taken from 8mm film and transfered to a DVD by a company that does this kind of thing. The resulting video will play from the disc in the DVD Player but when I open the DVD itself nothing shows on the disc in the way of files. I have tried a variety of applications to lexamine the disc and none of them even see the disc, it's as if there is nothing there on the desk top. I have tried a DVD ripper rogram and it doesn't see the disc and I have tried iMovie to import from the disc and it too doesn't see the disc. I would like to incorporate video from the disc into a family video if possible. Any suggestions???

Thaks

Andy