This issue may occur if you created a slideshow in iPhoto and then chose Send to iDVD from the Share menu, but you've never started iDVD before. To prevent this issue, make sure that you've launched iDVD at least once before using the share feature of another application to build a DVD. Once you've launched iDVD and it has written its preferences and other related files, you should not encounter this symptom.
Follow these steps to successfully burn a slideshow.
- Quit iDVD and then reopen iDVD.
- Create a new iDVD project.
- Go back to iPhoto and export the iPhoto slideshow to iDVD again.
Tip: You can create a slideshow in iDVD that gives you additional options.