Falling is a common dream theme. Most people experience a long fall only to wake up at the last second before hitting the ground. Or, maybe you hit the ground and wake up when you realize you've died. The sensation of falling in a dream can represent your fear of taking a leap of faith only to have it not work out. We express our fear of losing our footing in life through the sensation of falling from a great height in a dream. Throughout our waking lives, we are always trying to keep our balance. If we lose our balance or our ability to keep all of the balls up in the air (so to speak), we may experience a fall in a dream.
Also, dying on impact is not an indication of your own death. It is simply your minds' way of fully experiencing the fear of falling.