I recently purchased a new PC with Vista and had an immediate problem with burning DVD/CD's. I tried Nero 8, Win Media Player, and two other burner programs with no results. what would happen is the burn would fail (error message) when it was almost done.
I spoke to a Tech who said that this was a known issue, in which the burn will fail near the end due to some conflict between Vista and the DVD/CD burner driver. The fix he provided for me corrected the problem.
What I had to do was go to Device Manager and delete the DVD/CD drive as well as delete the registry key for it.
Once I restarted the PC, Vista found the DVD/CD drive and installed it's own driver to it and everything has been fine after that.
Thought I would post this in case anyone had similar issues.