You're not really working with a 10-hour timeline, are you? You can only fit about 60-70 minutes of video on a standard DVD -- maybe twice that on a dual layer disc.
In any event, the best way to find out what's going wrong and when is to use the troubleshooting steps in the FAQs to the right of the forum.
If you'll post the results for each step in as much detail as possible, we can help you figure out what's going wrong and how to fix it.
BTW, you're not combining MPEGs and AVIs in the same project, are you?
You definitely want to convert those MPEGs first to AVIs so that only DV-AVIs are going into a project and that project. It will certainly save you a lot of heartache (as well as having to deal with strange interlacing issues) later.
Along with Steve's link, you might want to take a look at this ARTICLE for details that would so very useful to help troubleshoot this issue.
There are also several recent threads, about the same, or very similar issues. You might want to do a Search of this forum and read, as there have been several contributing factors in those cases, and a lot of good discussion.