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;
});