In addition the project is no longer existing in I movie.
Yes this is most probably the reason. Things doesn't work as one would like but as they are constructed. E.g. there is no movie in an iMovie project but a small text document pointing to Event's folder and other libraries for material used in a simulated movie and then directions on howto they are meant to work together to play AS A Movie. (Parallel is the Conductor Sheet in a Concert. It will not play either but direct the Conductor on howto get his musicians to play it)
So when iDVD is to create the DVD it look's into iMovie Project's and Event's for material to creat the special .mpeg2 code from. And if it's empty. What to do ?
My strategy - would have to be:
• re-build the original movie in iMovie
• in iMovie "Share to Media Browser" and as Large (Not HD or other resolution - as this degrades the resulting DVD)
• close iMovie
• open iDVD
• import the movie from Media button/Movies - down right in iDVD window
• Save as a DiskImage
• Test this with DVD-tool
• Burn with iDVD or faster via Disk Util tool (set down burn speed to x2 or x4 to get best possibly result)
Yours Bengt W