Ok, the red circle is one of the tabs you will need to get past the big black plastic "tab" that the screwdriver is wedged between.
See that arrow there? Thats what happens when you position the screwdriver too low, get the screwdriver as close to the top as you can, the only reason it is so low in the pic is because, well, its flippin' hard to take pictures one handed and hold stuff right, lol.
All you have to do is leverage the handle of the screwdriver inward (toward the trigger, not away).
Just push on it until the little tab on the trigger piece is just inside the black tab, then, while keeping pressure on it with your thumb, do the same thing for the other side.
Viola.
Hope that helps!
