No sign of enemy action, in spite of what the Taliban may claim. Some reports of a load shift changing the center of gravity. That fits the video, but it is hardly conclusive. Other issues could include a faulty configuration for take-off or crew error. The B747-400F normally has an operating crew of 2, but this aircraft has 7 souls on board. All were lost.
[Update: Welcome, Ace of Spades Morons- Poke around a bit.]
[Update 2- Welcome Hot Air readers]
Here’s the Aviation Safety Network post with some background on the incident aircraft, carrier, airport and the incident itself.