It's not like one of those send or don't send errors, it says:
"The exception unknown software exception (0xc0000005) occurred at location 0x12afe0f2.
Click on OK to terminate the program."
It also happens if I launch a stickybomb in this area or hit a baseball as a scout. Maybe it has something to do with the physics? It's a TF2 map.
EDIT: It also happened when I shot an arrow as a Sniper. I also get a little notification at the top right of my screen when I am in my map saying "Warning: overflowed CClientrenderablesList group 7" Would that have anything to do with this?