I'm not an expert, so please don't put a lot of weight on what I say, but I read somewhere that dreams in which you are falling are a sign that you maybe feel, either consciously or subconsciously, that you have a lack of support from others in your life and feel slightly insecure - but it is not for me to say whether this is you or not.
However, if within these falling dreams you do not feel frightened, it is meant to signify that you are going to overcome your problems quite easily.
If you feel that any of these states of mind relates to you, if it is an issue of insecurity etc then maybe try speaking to someone you trust to see if you can conquor these problems and thus reduce the dreams.
However, you must remember that dream interpretation is not always reliable.
If the frequency of the dreams really does bother you, maybe just have a quick chat to a doctor who may know whats up.
Good luck and take care