Hi,
there are many reasons for CTD, and I have to say we are long way from seeing the last of them.
There are two main sources of CTD:
1. Rome Total War game engine memory hog.
There are instances of the animation not able to recover the memory used.
2. Missing animation files
Such as the city map CTD, where a file needed is missing.
The first type can crash at any time when an animation sequence requests certain memory or queue resources and these have been used up by the game engine, the software will CTD.
The second type only happened during loading.
So as you can see, if the problem is in the first category, you need to save the game periodically.
Also, it is known that when the first type of CTD occurs, it can corrupt the saved game file. So more reason to save the game.
And since the Amazon Total War being release or being worked on since 2005, there has never been an Amazon emissary causing a CTD. Because the memory load is not there to cause it, unless the game has already been corrupted by the prior battles.