Without seeing it, I would suggest trying this:
1. Remove the needle from the machine.
2. Hold onto the threader, and turn the handwheel until the needlebar is at its highest.
3. Gently but firmly, pull down the needle threader. When the part stuck behind the needlebar is below it, swing the threader forward/left (back to it's proper position).
I've never had this happen before, but this is where I would start. I figure, she got it stuck there without taking it apart, so hopefully it can be unstuck the same way.
A picture might make it easier to figure out, if the board is letting pictures post again...