that story about the falling dream is what i call a playground myth.
passed around from child to child at school when you are really young and just sticks in your head - you assume because you have known this fact as long as you can remember that it must be true.
The fact of it is dreams about falling can actually have lots of meanings depending on what you are falling from, and onto what you are going to land. The only reason you usually wake up before landing is the adrenaline rush you get from the exhileration of thinking you are falling and it becaomes too much just before you land and forces you to wake up, often feeling a bit anxious and sweaty - it's just the adrenaline. :D