This is about the crash that happens when you try to select a specific squad in the "Positions" section of the Military Screen. If you are unlucky enough that the first squad on the list is the one causing the crash, you probably get a crash every time when entering Military Screen.
It seems that the crash happens when one or more of the members of the crashing squad is assigned with large dagger as a weapon.
The exact cause seems to be DAGGER skill used by large dagger.
The workaround I found is changing this skill, my military screen no longer crashes after this change.
To fix it go to raws folder of your save, the path is something like
"<DFfolder>\data\save\region<whatever>\raw\objects",
find "item_weapon.txt" file,
find [ITEM_WEAPON:ITEM_WEAPON_DAGGER_LARGE] entry,
then change [SKILL:DAGGER] to some other skill, [SKILL:SWORD] seems the most appropriate.
Post in this thread if it fixed the crash for you.
Here is Bug Tracker report about this crash:
http://www.bay12games.com/dwarves/mantisbt/view.php?id=378 If you discover any new causes or workarounds to this crash, post in the bug tracker.
--I am posting this here because you can't make new threads in DF Bug Reports section of the forum.