The ATI drivers are not included on the free DVD because they are propriataty software. If this is the cause of your trouble, you can download a Mandriva One CD image for either Gnome or KDE (your choice). On the ftp mirror, in the directory for the One images, there is a README file. Read it to identify which of the six Gnome or eight KDE images to download for your language. If you use English, then use 'mandriva-one-2007-gnome1.iso' to get the Gnome desktop, or 'mandriva-one-2007-kde1.iso' for the KDE desktop. Note that if you choose either of the image files with 'free' in the file name, you will not get the ATI drivers, and will have the same trouble as with the free DVD.
The Mandriva One CD's are 'live' CD's, so when you boot the CD, you will boot into Mandriva Linux. From there you can install to your hard drive, then add sources to RPMDrake by following the directions provided in the README file mentioned above. Then you can add any software not already installed.
Other possibe causes are either a corrupted DVD image (you can check the md5sum), or a bad DVD burn. I do not use DVD's here yet (I'm too cheep, and my CD burner works OK
), but if I try to burn CD's at too high a rate or even at the stated supported speed of the disk, the burn is often corrupted. You may want to try using a slower burn speed if that feature is available.