This also happens to me. Whenever an archer kills a skull with bone item, the game crashes. Not sure why it does not happen on close range kill tho.
It's the case of Skulls AND funnybones item stacked on top.
Probably you would get similar problems with Summoners or rats with Funnybones (I can try to test this if needed) - something about the row being full, and both the unit AND the item trying to summon at the same time seems cause the crash (cuts directly to black screen)EDIT: I've done the experiment (see below). Looks like its only skulls for some reason.
Okay, nope, I've come back and checked it out:
Did my best to crash the game only using rats, summoners and funny bones (no skulls)
Turns out, for this set up even if my rats get shot and the row overflows, the game can handle it.
So... whatever error is going on, it appears to ONLY apply to Skulls with Funnybones on them.
Not sure why that is, but hope it helps.
EDIT: (That, or there's something special about dude's being shot in row one as opposed to row three... but this seems less likely to be the cause.)