He was the god of war, spring and youth.
He is sometimes the symbol of life and death.
In mythology, Ares was often beaten and humiliated by his enemies.
He was like an ill tempered child that was unable to receive the amount of credit that he desired.
Thus, seeing this planet in your dreams may be symbolic of your own frustrations that lead to aggressive thoughts and feelings.
Mars is a symbol of male energy.
This energy, when used in positive ways, creates permanent change and transformation.
The dream maybe encouraging you to get in touch with raw emotions and desires, to ponder upon them, and then to use them to transcend difficulties.