Not too uncommon in an MD11. I seem to remeber Korean doing the same in ANC as well a few years earlier. With the freight door at the front, it can be easy to tip it on it's bum if you've forgotten the tail stand.
My company flys 747Fs - we don't do any loading without a stand or a noseleg strop.
It's not too difficult in a Pax 747 either - as the air Canada picture shows. I was on the gate at a US airport when the load handlers loaded the rear bay before the front - against SOPs. We were in the cockpit preparing for the flight when the aircraft went into flight mode. We quickly realised the nose leg microswitch had opened. A very quick call to the groundcrew stopped the situation, but it was close.