If you are unable to find your locker or unable to open your locker in a dream, then ask yourself what you are feeling unprepared for in waking life? Are you feeling un-equipped to deal with something or someone right now?

The locker can also represent your identity as it is where you keep your personal belongings, in which case not being able to find your locker would suggest that you are not sure of your place in life or perhaps in career or even in a social circle.