Animation Vibration

Hi
I have a bad problem!
first download my attachment.
in this simple game you see a Player that walk Without any movement!
until now everything is OK!
but when i put right arrow key down to walk right you see the leg of my player starts to vibration ? do you see?
I don't know why? if problem relates to my animation, but why when player is static this problem doesn't happen!!
can any one help me?
Please.
I have a bad problem!
first download my attachment.
in this simple game you see a Player that walk Without any movement!
until now everything is OK!
but when i put right arrow key down to walk right you see the leg of my player starts to vibration ? do you see?
I don't know why? if problem relates to my animation, but why when player is static this problem doesn't happen!!
can any one help me?
Please.
