Dafydd, I've done a few tests this evening, and here are my findings...
The first time I created the project (captured video in Mpeg format, some background music, Titles, stills, transitions and 15 chapters ), the burn failed (either to Disc or to the hard drive). I then continued testing, always writing to the hard drive.
I then REMOVED all the chapters, and it worked. Nothing else changed in the project. I then added ONE chapter for a total of 2, and it worked.
The original chapter names all varied in length. It's interesting to note that there is no character maximum when renaming a chapter - its based on the width of the name. For example, I could only enter a maximum of 15 "w" as a chapter name, 20 "o" or 60 "i". Because of the different widths of these characters, there's no actual maximum. The way around this (and likely a bug in the software), is to rename the Title corresponding to the chapter on the DVD Menu screen. When I change the title name to "This is a test of a long name", and then go back to the Chapter list, this full name appears. However, if you try and rename it, you can only enter "This is a test of a long na". Some very odd behaviour indeed.
It's odd that renaming the thumbnail title on the Menu actually renames the Chapter itself. The other odd item I noticed on the original project (the one which kept returning the error), was that Chapter 1 started at 00:00:00:26? This is very odd, as Chapter 1 should ALWAYS start at 00:00:00:00. I couldn't reproduce this behaviour with a new file.
Anyway, I then removed ALL chapters and produced it as an Mpeg (Mpeg2, DVD HQ). I created a NEW project and brought the Mpeg back in, added chapters and the burn worked! I then renamed the chapters (in the chapter room, NOT on the menu), added a background image to the menu and the burn worked!
I then went back to the ORIGINAL project, removed ALL chapters and re-added them back again. Chapter 1 started at 00:00:00:00, as it should. I then renamed the chapters (again, in the chapter room), added a background image to the menu and the burn worked. All the media was still in the libray, I never removed it.
I'm almost convinced that the error has to do with the chapters. When I took a look at on of the projects which was failing, chapter 1 had a start time of "282343:52:24:-11" ? I've found that you can bugger up the chapter list by REMOVING chapter 1. If you right-click the chapter, the option to remove is greyed-out, however, the "Delete Chapter Position" button will actually remove it, and all the chapters slide up. The chapter names then become messed up when you leave the Chapter room and go back to it - in my case, the Title of Chapter one became "Chapter 15"? Again, some very odd behaviour.
So in my particular case, the issue was resolved by removing all Chapters and re-creating. I then renamed them in the Chapter room and NOT on the menu. I haven't been able to reproduce this by creating a new, short movie using the Aquarium.mpg and renaming items on the DVD menu. It always burns successfully.
I hope this information helps, sorry about the length, I was trying to be as descriptive as possible.
Regards,
Shaan