I do hope MS staff observe this thread.
I also encountered this problem when I ran out of (cheap, rubbish DVD-Rs) and replenished with some (dearer, branded) DVD-Rs only to find that WDM spat the dummy writing to this media, even though (a) the project wrote to other media previously and (b) other writing software can successfully write to the same media. With source material and the media conclusively ruled out as being at fault, WDM is the culprit.
Right now I'm actually more pissed off that this program handles the process so poorly such that any error in burning infers having to go through the entire (lengthier) encoding process again from scratch. Where's the write to file option to avoid this?! So inefficient it's laughable. Shame really, as in other respects I quite like the software.
Sadly, my time is too valuable to wait so many hours for each attempt so I will have to purchase some additional software that can at least complete the required job in a timely fashion.
Shame.