Here's the deal:
I'm using Windows XP, a Pioneer DVR-106D DVD burner, Nero 18.104.22.168. (latest version) and Memorex DVD-R 8x blank DVDs.
I can burn the DVD fine, without any errors. However, once I try to see the files I've just burned: I can't! At first I got a "D:\ not accessible - Incorrect Function" error (I got this when trying to access a blank DVD as well). I've since activated Windows XP "click-and-drop" burning and can now open the DVD, but there's nothing in it and it says 0 bytes.
However: If I try to access my newly burned DVD on another of my Windows XP machines it works! All the files are there and can be copied/used without any errors.
What's going on here anyone