Slerp Problem?: Enemy in Constant Rotation!

I am having a problem with an enemy in my game where the enemy is constantly rotating. I used Quaternion.Slerp to control rotation. Here is my script:

@script RequireComponent(CharacterController)
   
public var MarManRotateSpeed : float;  
public var attacktarget : Transform;   
private var selfplace : Transform;    
// [...] 
   
function Start()    
{    
	selfplace = transform;   
}
function Update(){}

function CoUpdate()    
{   
	Debug.LogWarning("Success?");    
	while(true)    
	{
        // [...]    
	    var target : Transform;    
        target = attacktarget;
        selfplace.rotation =  Quaternion.Slerp(selfplace.rotation,
                                Quaternion.LookRotation(target.position-selfplace.postition),
                                MarManRotateSpeed * Time.deltaTime); 
        // [...] 
	}    
}

Am I using Slerp wrong? How do I fix it?

I am creating a link to a similar question. Although it refers to “Lerp,” it should help explain how to use “Slerp…”

http://answers.unity3d.com/questions/230832/how-to-use-lerp.html