Our brains like to pick up on things that we see repetitively or actions that we repeat normally. To see the Buddha in your dreams suggests that you may have just seen him one too many times in other ways. If this is a recurring dream and you want to make sure that it is not this, try actively avoiding areas of your town that are active in proliferating Buddhist culture. Try to turn on the TV as little as possible and try to keep yourself locked away inside your house away from where you can be easily influenced by civilization for as long as possible. If you are able to keep away from the Buddha and you are still seeing him in your dreams, then this means something entirely more important.
A big idea in Buddhism is the idea of becoming Zen or of reaching nirvana. The Zen philosophy is one that could take books upon books to describe accurately so a few sentences do it no justice. But the main idea behind Zen is the idea of being peaceful and of communing well with the world around you. You are becoming a part of your surroundings, but you are not blending in to your surroundings exactly. The level of peace that you feel must be great though. You must radiate the idea of peace from all of your pores and from within you as a person. This is who you are and you are dedicated towards peace. To dream that you see the Buddha suggests that you may have reached a Zen state. Though to be honest, if someone were Zen, then they would know it. If you were truly practicing the philosophy then you would not need to be told you were doing a good job through your dreams. It could just mean that you need to aspire to be more Zen to greater lengths. Do more than you could have ever imagined doing in order to achieve your goals.
To dream that you are seeing the Buddha could suggest that you need to try a little harder to reach nirvana. Nirvana is again, a concept that would take book after book to explain, but for a little bit of background on it, nirvana is much like the Christian concept of heaven, but you can almost achieve it in life through the art of Zen unlike heaven, which in Christian studies, you are told you must die before you can reach. If you have been trying to be a better person in order to receive some sort of return, then this might mean that you are getting a bit closer to reaching your own personal nirvana. The afterlife will treat you well if you so wish it to be. But you do not have to wait until the afterlife. You can have it now if you try hard enough to be a good person. All you really have to do is shoot for the moon and try to remain peaceful.