Why does animation affect rotation?

I have a model, that is move in game by this script:

void Update ()
	{	
		if (Walk == true&&transform.position!=Target.position)
		{
			float step = Speed * Time.deltaTime;
			transform.position = Vector3.MoveTowards(transform.position, Target.position, step);
			transform.rotation = Quaternion.Slerp (transform.rotation, Quaternion.LookRotation (Target.position - transform.position), RotationSpeed * Time.deltaTime);

At the same time I try to play an animation, that I imported from 3dmax (fbx).

The problem is, when I use the script without the animation, the model rotates in the direction I need, facing towards the point of movement. But when I use the animation (basic walking animation), the model faces the opposite direction when moving.
I have no idea why can this be happening, so I have to ask for help)
Thanks in advance!

The animations you have used are offset in the wrong driection, in the right hand side if u doulble click the animation a few times it will have a box in right u can click a star thing in bottom right and pick a modle ie your avatar, then play the animation with the little play icon above , if it goes wrong then its the animation not aligned to Unity.