One of the most frequent complaints about Vista is a faulty installation...files not found or it simply losing track of where it was seems to have plagued users since early in Beta 1. The first suggestion is always to burn a fresh copy at a slower speed to decrease the chance of a faulty burn. However, some say that there are compatibility issues with various DVD-ROM drives, so the problem even occurs using a pressed DVD from Microsoft. The answer to that is using a DVD emulation program such as Daemon Tools, which lets you install Vista without burning the ISO or even having an optical drive. Success rate using that method of installation is near 100%.

Good luck.
John