A single crane operator was called out late night to offload equipment from a truck. The crane operator offloaded the truck with a fork truck without performing and pre-job or JSA type review. The last piece of equipment removed from the truck trailer was a 5¿X5¿X7¿ tool box (6580 pounds). As the tool box cleared the truck trailer, the fork truck operator reversed and started lowering the load to the ground. Presumably, to remove the dunnage boards from the trailer, the contract truck driver walked between the load and the trailer. The fork truck operator halted lowering the load in an attempt to stop the driver. At this time the tool box unbalanced and fell forward off of the forks, pinching the truck driver between the tool box and the truck trailer.