Can you try copying the contents of the DVD to a folder on your hard drive, and install from there? I don't know if the install will work, but if you can copy the files ok that would rule out a problem with the disk as well as a conflict or problem with the optical drive.

I've run into different optical drives reporting different corrupt files on burned DVD-Rs, as a result of a bad piece of memory. It isn't hard for RAM sticks to just get bumped loose during shipping, and have problems that could be fixed by removing and reseating it. I don't know if I'd bet both problems above are due to that, but it is something worth checking.

Memtest86

MS Windows Memory Diagnostic