DVD woes

I've been having the most puzzling problems with my big video project. I'm at the stage of burning it to DVD, and I can't get the audio on to the DVD. My basic workflow was

- edit in Final Cut with chapter markers
- export from Final Cut as Quicktime movie, audio and video included, with chapter markers
- bring into iDVD
- create disc image using iDVD (saves time on each burn)

It's this final file, the image (or disc) where the program audio isn't audible and probably doesn't exist. My technically proficient friend is helping me work this out. So far we've identified or heard of these potential problems:

- iDVD can't include the audio because my hard drive is too full (it is....)
- chapter markers mess it up
- my version of Quicktime doesn't work with my version of iDVD
- the sound track doesn't come through because it's 1/100 of a second shorter than the video (it is)
- there's a problem with the five-second slug appearing right at the beginning before the opening credits (there wasn't on the last, basically identical project).

So far, only one thing has worked while keeping chapters. Using iMovie, under my friend's account on the same iMac, stripping out the opening credits and adding several new chapter markers throughout the video.

Looking at that result, the problem may be with the opening credits or slug. So I may be able to go back into Final Cut, redo those elements, export it, and add the chapter markers in iMovie.

But what a nightmare. I just want to get this thing out there and get all this footage off my hard drive!!