Dog growling at 2 yr old daughter

Question
I have a medium sized female black lab mix. We got it at a shelter as an older puppy (was told it was younger than it was) The dog is a almost two years older than my daughter and is the only pet in the house.

Since she was a walking toddler, my daughter and the dog have had a good relationship. On the accidental step on, the dog has yelped or grumbled and gotten up. (Mind you the dog does not get up when you walk near it and will wait until asked 2-3 times for my husband and I to move so we can pass-would love advice on how to teach her to get up when we walk towards her) In the last few days the dog has growled at my daughter a few times. Twice it was after a few minutes of playing with my daughter and then she either fell on her or stepped on her. Another time seemed to me unprovoked, but my daughter was walking through to the sofa and accidentally fell on her. Today my daughter was walking out of her bedroom and the dog was laying right in the doorway. My daughter may have stepped on her or something and the dog growled at her. (I was sitting right there on the floor but my back was turned) I'd really like to get my dog to stop growling so that I don't fear her biting my daughter. Secondly, if I could get her to move when people walk by that might avoid things altogether.

Answer
This sounds like a leadership issue.  Every time she makes you step over her or go around, she is signaling she is in charge.  The key to most behavior problems is approaching things using the dog's natural instincts. Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog. Life is much easier if the 2 legged pack members outrank the 4 legged ones. You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/ For more on being top dog, see http://www.dogbreedinfo.com./topdogrules.htm   You need to follow the link on that site to their material on dogs and children too.  

In addition to the standard basic obedience, you will need to teach ''Move!''.  Use its name followed by move.  Gently force it out of the way or lure it with a treat and then praise it.  It should catch on and move on command  before long.  Lower rank dogs must move out of the way of higher ranking ones.