I have this problem too. I've been trying for over a week just to burn a dvd, and nothing has worked so far.
Using LG GSA-1466B
Nero7 Ultra Edition, demo
once i was able to erase the DVD, but never burn.
other software attempted were
Sonic (which came with my PC)
Nero (whatever came with my DVD burner and was removed when i installed this Nero7)