Dvd_Rw has a problem as I had.
I think if you burn a DVD and nero says it's empty it's due to bad quality media.
I had same problem with Sky Media DVD-R .
Burning process took 30 or 55 minutes and I have a "Succesful burn" message but the disc was empty.
As it was empty, I tried to burn again on it and then nero freezed at 2%, trying to write the track.
I'm using Memorex at the moment and I don't have anymore that problem.
Hope this helps.