Changing the walk animation on PlayerAdded?

I have this line of code in a PlayerAdded function and I'm not sure why I am getting an error. Here is the code

player.Character.Animate.walk.WalkAnim.AnimationId = "http://www.roblox.com/asset/? 
id=252557606"

Now there is nothing wrong with the variable player as i was able to use it in other lines of code in this function. Here is the error message

ServerScriptService.Leaderboard:16: attempt to index field 'Character' (a nil value)

Any help is appreciated :)

SORRY I FIGURED IT OUT thanks for reading anyway