Lets take things one step at a time.
What is the Project Preset, that you chose, when you did New Project?
Now, we'll look at your Assets:
Can you tell us the size in pixels x pixels for your still images, and their format, i.e. JPEG?
With your Video Assets, please make a list of their specs - one set of specs for each file type/format. The free utility, G-Spot, can get that info for you. Be sure to note the Frame Size, and especially the CODEC used for each, plus their Audio data.
Last, take a good, close look at your Timeline at about the 36% of total Duration point. What Clips appear in that general area? Zoom in onto your Timeline (to the Frame view level), and look very closely for any gaps in the Video Track (gaps in the Audio Track are OK). You might want to post a screen-cap of the Timeline at approximately that point. It would be helpful to include the Project Panel, scrolled to the Assets at that point.
Note, MP3 Audio files can be highly problematic. I always convert any of these to PCM/WAV. The free audio-editor, Audacity, is very useful for doing this, and the good news is "it's free!"
It is most likely that your Assets, and possibly a mis-match between some of these and your Project Preset, are causing this issue. It could well be that you will need to convert certain Assets for use in your Project. When one mixes Assets, it is often best to pick the specs. of one, and convert all others to those specs.
Good luck, and let us know the details - the cure is probably within those.
I took a bit a different route. I checked for gaps in the video and the size of still images. I then saved the project as an MPEG, reloaded it as a new project under a different name and it seems to have burned just fine. If there are other issues that come up, I'll pass them along.
The only downside to Exporting/Sharing as an MPEG is that the program will then Transcode to MPEG-2 for the burning of the DVD.
With an SD Project, the better Export/Share would be to DV-AVI Type II w/ 48KHz 16-bit PCM/WAV Audio. That will save having two compressions to MPEG.
I try to keep any compression out of the workflow, until absolutely necessary. Note: DV-AVI will compress, but only slightly, and it is almost impossible to tell that compression, even on a calibrated CRT monitor.
PS - Gaps can cause all sorts of problems. Good work checking for those!