multi-movie burning

[Teacher]

 have tried everything to burn multiple movies to one DVD. I'm wanting to
burn more than 6, so I have set up folders and all. I have been successful
with a multi movies up to 5 inseperate folders, but now it kicks out the DVD
without any error message...it usually happens during stage 2. Are there any
settings I need to check? Has anyone burnt more than 6 movies successfully?
I'm using iDVD 3. I have looked in the archives of this mail list as well as
Apple's. Everyone talks about how to get the movies into an iDVD project
which I can do, but nothing about what to do when it won't burn more than 6
movies.

Thanks in advance for any help.