DDT script only works on one terrain

Hello Everyone,

I have a dynamic destructible terrain script that works perfectly one terrain I have (the only one in the scene). The purpose of it is to make craters upon collision with my projectile. Unfortunately, when I apply the script to a different terrain inside a different scene, the script fails to work! It is very annoying, as I have fiddled around with the code as much as I could and have not been able to solve this issue. Code:

 private var tData : TerrainData;
 private var saved : float[,];
 var cratertex : Texture2D;
 var xRes;
 var yRes;
 var craterData;
 
 
 function Start () {
     tData = Terrain.activeTerrain.terrainData;
     xRes = tData.heightmapWidth;
     yRes = tData.heightmapHeight;
     saved = tData.GetHeights(0,0,xRes,yRes);
     craterData = cratertex.GetPixels();
 }
 function OnApplicationQuit () {
     tData.SetHeights(0,0,saved);
 }
 function OnCollisionEnter (hit:Collision) 
 {
 if (hit.gameObject.tag=="projectile")
     {
     var x : int = Mathf.Lerp(0, xRes, Mathf.InverseLerp(0, tData.size.x, GameObject.FindWithTag("projectile").transform.position.x));
     var z : int = Mathf.Lerp(0, yRes, Mathf.InverseLerp(0, tData.size.z, GameObject.FindWithTag("projectile").transform.position.z));
     x = Mathf.Clamp(x, cratertex.width/2, xRes-cratertex.width/2);
     z = Mathf.Clamp(z, cratertex.height/2, yRes-cratertex.height/2);
     var areaT = tData.GetHeights(x-cratertex.width/2, z-cratertex.height/2, cratertex.width, cratertex.height);
         for (i = 0; i < cratertex.height; i++) {
         for (j = 0; j < cratertex.width; j++) {
             areaT [i,j] = areaT [i,j] - craterData[i*cratertex.width+j].a*0.01;
         }
         }        
     tData.SetHeights(x-cratertex.width/2, z-cratertex.height/2, areaT);    
     }
 }
 
 

I appreciate your help, in any coding language except Boo. -Hyperion