What does this re-occurring dream mean?

I'm awake in the middle of the night. I'm standing at the bottom of my stair case when suddenly I look up the stairs. There is the dark silouette of a big, tall man. I try as hard as I can to scream and run for my parents. But no matter how hard I try, all that comes out is a croak of my voice and I can not move. The man runs down the stairs and wraps an arm around my neck and the other is keeping me back. Then two other men (I can't see any of their faces, just dark shadows) come running down the stairs and out the door. The man holding me back let's me go, and laughs the scariest, creepiest, very evil laugh and runs out too. My family has never been robbed and our house never been broken into. But ALL my life, I am scared to death that it will happen. I used to live in Phoenix two years ago and I was born there. so maybe I developed the fear then? Anyway, could the dream mean something? I've ALWAYS had the dream.