The way I heard it, is that the Canadians were holding a live ammunition training excercise at night. An F16 overflew it and saw it going on, and reported that he was taking fire. He radiod in and asked permission to attack. Denied, but was given permission to mark the area for a strike at some point in the future. He marked it, and requested permission to strike at it. Denied. He reportedly said that he was taking additional fire and decided to invoke his right of self defence and proceeded to strike at the troops on the ground.
I kinda have a hard time believing that these Canadian troops were firing at the F16... It's not like it could have been mistaken for a jet belonging to the El Quada air force.
Screw up? Or some out of control F16 jocky?