That's odd. Playing it myself, with no mods, the latest beta patch and the addon installed correctly, I never crash at all. Neither have many other testers. Are you sure you're running without mods? That you installed the addon correctly? Or that, if you're using beta patches, that they're enabled properly? I can only see it being something clientside. It's also very odd that the AI isn't engaging you. Perhaps that's also related to said possibilities?
I will say that since, I believe, patch 1.05 of ArmA, preloadCamera does not work anymore, and still doesn't seem to in ArmA II. I've tried to minimize their effects on my missions wherever possible, but it seems impossible to get it 100% unless all angles are within the same general area.
Also, the AI is not spawning. The only time they're randomly placed is at the start of the mission, and you don't see it as they're in the town. It happens immediately after the mission starts. This is due to Kronzky's UPS.