A camera in a dream often points to how you observe your own life, or how carefully you're documenting a memory you don't want to lose. A camera that won't work can reflect frustration at not being able to capture or control your self-image the way you'd like others to see it.
Mercury conflicts with those who are ruled by Jupiter, and Jupiter conflicts with those ruled by Mercury. - Picatrix (Andalusia, ~1000.AD)