Just looked at your sourcecode and saw that this crash happens, when a trigger isn't found in triggers.

I was adding orders, when it happened. There where some orders left from before and I added some torches. Directly after giving the torch orders I gave a dig order, then it crashed.

Edit: Had the same crash again, when clicking with a torch order an imp.

On Windows 8 btw.

Edit: The game crashed 5 times with an unknown error.