Help with my Flocking Algorithm

 @HideInInspector var averagepos : Vector3;
 @HideInInspector var keepaway : Vector3;
 @HideInInspector var matchvel : Vector3;
 var raptor : GameObject;
 var raptorarray : GameObject[];
 
 
 function Start () {
 }
 
 function Update () {
 raptorarray= GameObject.FindGameObjectsWithTag(raptor.tag);
 
 if ( raptorarray.length == 1)
      return;
 else 
  {
              for (var l = 0;l<raptorarray.length;l++)
              transform.position = transform.position + rule1(raptorarray[l]) + rule2(raptorarray[l]) + rule3(raptorarray[l]);        
  }
 }
 
 
 
 function rule1(rap : GameObject) //keep to the average position of the flock
 {
     var pos : Vector3 ;
     for (var i= 0; i<raptorarray.length;i++)
     {
         pos+=raptorarray[i].transform.position;
     }
     averagepos=pos/raptorarray.Length;
     return averagepos/100;
 }
 
 function rule2(rap : GameObject) //avoid other objects including others in the flock
 {
     var away : Vector3;
     for (var i= 0; i<raptorarray.length;i++)
     {
         var distance :float = Vector3.Distance(rap.transform.position, raptorarray[i].transform.position);
         if (distance < 1)
         keepaway = rap.transform.position + (rap.transform.position - raptorarray[i].transform.position);    
     }
     return keepaway;
 }
 
 function rule3(rap : GameObject) //match the velocity of the others in the flock
 {
     for (var k=0; k<(raptorarray.length);k++)
     {    
         for (var i= 0; i<(raptorarray.length-1);i++)
         {
             if(rap.rigidbody.velocity != raptorarray[i].rigidbody.velocity)
             {
                 rap.rigidbody.velocity+= raptorarray[i].rigidbody.velocity;
                 rap.rigidbody.velocity/=2;
             }
         }
     }
     matchvel=rap.rigidbody.velocity/8;
     return matchvel;
 }

I pasted all the code because I don't know exactly where my problem is. Basically when one enemy spawns on his own everything's fine, but as soon as the next one spawns, they both disappear and I get the error message "transform.position assign attempt for 'Enemy 1(Clone)' is not valid. Input position is { 244941330874883540000000000000000000000.000000, 13465854283936009000000000000000000000.000000, Infinity }. UnityEngine.Transform:set_position(Vector3) Flocking:Update() (at Assets/Flocking.js:20)"

I get the feeling there's something wrong with my rule1 procedure but I'm not discounting the possibility of the others being buggy too. Can somebody please help?