Audio Mixdown Problem (midi fails, wavs work)

This is actually for Cubase 5, but it’s difficult to get help in that forum. This is C5, so clearly, I’ve been using it for a while and know the basics of exporting my mixdown. I have zero problems exporting other projects, but this one project has problems on multiple computers. Whenever I try to do a mixdown, the resulting audio file will play just a couple of notes that came from midi, and then it goes silent. As an experiment, I decided to include a wav file and that wav file plays just fine in the mixdown. I’ve never experienced this before. Any ideas? Thanks.

Guess it’s time to just rebuild everything in a new project.