As for the civilians, with the ban on radio and television by the Taliban, there would be little knowledge when an immenent attack would take place. The Taliban I imagine would have been informed or would know but passing it on to the locals may not have been high on their agenda.
As for packing and leaving the area - during world war two in Sicily, my grandparents apparently stuck around in the village when the Allies were kicking the Germans out. It wouldnt have been in their mentality to pack and leave, as their whole 'world' from birth to death was the village. I imagine most Afghans live a 'village life'. The ones that do evacuate are probably the ones who have had their town destroyed.
Myself, I'd fill up the car with fuel and go into the bush as well if there was an immenent attack.
As much as I have been rambling that USA is bad for the bombing etc etc, the Taliban did fail to organise evacuation of the civilians - and thus they must take much responsibily for these deaths too. At this point, the Islamic groups (taliban, bin laden etc) have scored a lot of propaganda points.