Problem with Rigidbody2D and Collider2D when animation from spritesheets attached.

Hi, I was trying out different ways to animate characters for my 2D game in Unity 4.3.4 and tried out spritesheet animation (by slicing the sprite using grid option in sprite editor. Followed instructions on - http://michaelcummings.net/mathoms/creating-2d-animated-sprites-using-unity-4.3#.Uyazts9WHIU).

However, When I create animations using this method, the animations play well on the gameobject (using animator component attached to that gameobject) but Rigidbody2D and BoxCollider2D doesn't seem to work after Animator is attached. The character is neither affected by gravity nor does it collide with other gameobjects. Please help.