Problem with AW.UI.List Popup Template

I'm using the "onblur" event to determine if an item has been selected in a list. If no item has been selected, I want to alert and display the popup again.

However I get an error message saying: An unhandled win32 exception occured in IEXPLORE.EXE [2812].

The offending line of code is: obj.getCellTemplate(2, arrInfGridData.length-2).showPopup();

Any ideas why this is happening?

obj.setPopupTemplate(function(col, row)
{
   var list = new AW.UI.List;
   list.setId("CellComboList");

   if (bitAdding == true)
   {
      list.setItemText(arrListData);
      list.setItemCount(arrListData.length);
   }
    

   list.onItemClicked = function(event, i)
   {
      bitUserSelected = true;
      var selectedText = this.getItemText(i);
      obj.setCellText(selectedText, col, row);
      obj.setCellValue(selectedText, col, row); 
      obj.getCellTemplate(col, row).hidePopup();
   };
    
    
   list.setEvent("onblur", function(event)
   {
      if (bitUserSelected == false)
      {
         alert("Please select Resource Type");
            
         obj.setCurrentColumn(2);
         obj.setCurrentRow(arrGridData.length-1);
         obj.setSelectedColumns([2]);
         obj.setSelectedRows([arrGridData.length-1]);
            

         [i][b]obj.getCellTemplate(2, arrGridData.length-1).showPopup();[/b][/i]
      }
   });
    
   return list;
});