Never had a problem with the game crashing before, first post ever.
Hi pacotaco, welcome to the forum!
This is the same issue as reported already before few days ago. There is a map node with negative Z coordinate (probably in DESERT13.RMP).
This will be fixed in the next piratez release.
In the meantime, since you know how to turn on debug mode, I suggest to cheat a little and kill all aliens (Ctrl+K).
Or just abort the mission before it crashes.