You could always try the trick that was mentioned on here last week of holding the door opening knob in the open position for 5 seconds which has been known to open the boot on some chim's. Depends what's broke I suppose.
I tried that before it broke and that didn't work, I've just read in the bible how to open it but haven't had a chance today but will start there I think. (I tend to pick the wrong end to start)