if a race (like Kobolds and orcs) are kidnappers it will spam the game they are kidnapping creatures when they carry them off the border... this isn't the reason for your crash. Its most likely a memory fault. generally with the really modded Civilizations (which right now is all of them in MWDF) I've had 4 primary game crash points all centered around trading:
1. unloading of caravans by merchants(graphical image changing selection drops fps to 0),
2. setting trader requested at Depot(I think the game is working out values of items, too many items and its locking),
3. caravans loading up, and
4. caravans leaving the map (I think its more math being worked out for how much you sold and how this effects rep and other things).
all 4 of these I can get past by quicksave.
1a. Quicksave when the caravan appears at map edge.
1b. Quicksave after caravan is set up.
2a. Quicksave prior to setting trader requested at Depot.
3a. Quicksave after trades are completed.
3b. Quicksave when it says they will embark soon.
4a. Quicksave when they move out from Depot.
4b. Quicksave when they are exited from the map.
the entire issue around caravans is they are memory Hogs. when they show up they bring a thousand new items for every mob on the map to consider when selecting jobs, theres a lot of Civ/trade "math" going on in the background. They leak all over the place causing memory failure eventually, In Vanilla DF on a common 1G ram laptop, running 2 years through 3 trades a year(i.e. No pause, No restart, straight through) will eventually lead to a crash on its own. Add in the massive amount of dfhack scripts that are ran for the "Modded races", along with special buildings, and other things.... well not every computer is created equally. by a 3 or 4th year fortress, I quicksave every 10 in game days and restart the game every 3 months or every caravan arrival, just to avoid crashes related to memory leaks/faults.