I made a small change to the Action that comes with the 2DTK download from here 
https://hutonggames.fogbugz.com/default.asp?W717All i did was change the PlayAnimation action so that I didn't to add a StopAnimation action before every play animation action.
// (c) Copyright HutongGames, LLC 2010-2012. All rights reserved.
using UnityEngine;
namespace HutongGames.PlayMaker.Actions
{
    [ActionCategory("2D ToolKit/Sprite")]
    [Tooltip("Plays a sprite animation. \nNOTE: The Game Object must have a tk2dAnimatedSprite attached.")]
    public class Tk2dPlayNewAnimation : FsmStateAction
    {
        [RequiredField]
        [Tooltip("The Game Object to work with. NOTE: The Game Object must have a tk2dAnimatedSprite component attached.")]
        [CheckForComponent(typeof(tk2dAnimatedSprite))]
        public FsmOwnerDefault gameObject;
        [RequiredField]
        [Tooltip("The clip name to play")]
        public FsmString clipName;
        private tk2dAnimatedSprite _sprite;
        private void _getSprite()
        {
            GameObject go = Fsm.GetOwnerDefaultTarget(gameObject);
            if (go == null)
            {
                return;
            }
            _sprite = go.GetComponent<tk2dAnimatedSprite>();
        }
        public override void Reset()
        {
            gameObject = null;
            clipName = null;
        }
        public override void OnEnter()
        {
            _getSprite();
            DoPlayAnimation();
        }
        void DoPlayAnimation()
        {
            if (_sprite == null)
            {
                LogWarning("Missing tk2dAnimatedSprite component");
                return;
            }
                _sprite.Play(clipName.Value);
            
        }
    }
}