In psychoanalytic technique, walls are generally held to be a symbol of the male personality, with a focus on power. This thinking seems to stem from the impressions a young child would have of dominant male power in the home (which is a "fortress" surrounded by walls and dominated by the patriarch). In dreams, many people encounter walls as a random barrier and/or a projection of power.
In your dream, do you come upon a wall in your travels, or do you find yourself immediately surrounded by walls?
Do you try to scale the wall, find its end, or simply ignore it?