Dreams dictionary: Plank

Dreams dictionary: Interpretation 1
To dream that you are walking the plank suggests you are feeling emotionally vulnerable. You are plunging into new emotional territory.
Dreams dictionary: Interpretation 2
To see a wooden plank indicates something that is in need of repair or that you need to maximize your resources and make something out of seemingly nothing.
Dreams dictionary: Miller Dream Interpretation
For a young woman to dream that she is walking across muddy water on a rotten plank, denotes that she will feel keenly the indifference shown her by one she loves, or other troubles may arise; or her defence of honor may be in danger of collapse. Walking a good, sound plank, is a good omen, but a person will have to be unusually careful in conduct after such a dream.