Found the problem. It's something that existed since KDFW was released, a single object name was mis-typed so the sim couldn't find it. However, while FSX just ignore it, it seems the same issue in Prepar3D will crash it.
To get the updated files, select "Check Live Update" from the "Couatl powered products" menu, and allow the Updater to run. Then, exit from the sim and restart it.