need help croping texture.... something wrong with my guigroup.

 var textBG             : Texture2D;
 var textFG             : Texture2D;
 var textGroup             : Texture2D;
 var textFGMaxWidth     : float;         //the starting width of the foreground bar
 var currentHealth        : float;
 private var btnHealthX  : int;
 private var btnHealthY  : int; 
 private var btnHealthWidth : int;
 private var btnHealthHeight : int;
 var a : int = 0;
 var b : int = 0;
 
 function Start()
 {
 
     textFGMaxWidth = textFG.width;
     currentHealth = 100;
     
     btnHealthWidth = Screen.width/3;
     btnHealthHeight = btnHealthWidth/8;
      btnHealthX=btnHealthHeight*1.5;
      btnHealthY=btnHealthHeight/2;
 }
  
  
 function OnGUI()
 {
 if (GameControllerScript.isPause || EnemyBulletCollision.isPlayerDestroyed || GameControllerScript.gameOver) return;
     if( !GameControllerScript.isHealthFall )
     { 
     // var newBarWidth : float = (currentHealth/100) * btnHealthWidth/1.23;
     }
     else
     { 
      currentHealth = GameControllerScript.maxHealth; 
      var newBarWidth   = (currentHealth/100) * btnHealthWidth/1.23;
       //print("" + newBarWidth);
     }
 
            GUI.BeginGroup( Rect (btnHealthX + btnHealthX * 2,btnHealthY + btnHealthY * 1.6,/*x and y*/(btnHealthWidth/1.23)*((currentHealth/100)),btnHealthHeight - btnHealthHeight*1.6),textGroup);
            GUI.DrawTexture(Rect (btnHealthX + btnHealthX * 2,btnHealthY + btnHealthY * 1.6,/*(btnHealthWidth/1.20)*/newBarWidth,btnHealthHeight -  btnHealthHeight*1.6), textFG);
          //GUI.DrawTexture(Rect (-a,-b,textFG.width,textFG.height), textFG);
          GUI.EndGroup();
       GUI.DrawTexture(Rect (btnHealthX*2.37,btnHealthY,btnHealthWidth,btnHealthHeight), textBG);
   
 }

tried applying texture just to guigroup but could nt get any results. no texture drawn. i am trying to crop texture in group