bool multi-dem array out of range

XCount=4;YCount=4;ZCount=4;

in MultiDem.cs I wrote:

 public static bool[,,] BoolArray (int a, int b, int c) {
     return new bool[a,b,c];
 }

log: IndexOutOfRangeException: Array index is out of range. (wrapper managed-to-managed) object:ElementAddr (object,int,int,int) spawnWalls.Start () (at Assets/Zanzarah_2/Map Generator/spawnWalls.js:16)

 var XCount:int ;                 
 var YCount:int ;     
 var ZCount:int ;
 private var t1:int;                    
 private var t2:int;
 private var t3:int;    
 function Start()
 {
 var CkBk = MultiDim.BoolArray(XCount+2, YCount+2, ZCount+2);             //проверка наличия блока    CheckBlock
     for (t1=1;XCount;t1++)
         {
         for (t2=1;YCount;t2++)         
             {
             for (t3=1;ZCount;t3++)
                 {
                 CkBk[t1,t2,t3]=false;    
                 }
             }
         };
     CkBk[1,1,1]=true;            
 Debug.Log("CkBk[1,1,1]= " + CkBk[1,1,1] + "CkBk[1,2,1]= " + CkBk[1,2,1]);                     
 }