>oExcel.ActiveSheet.Range("K:22").Formula = "=SUM(K19;K16;K10;K7)" >Unfortunately I didn't have Excel installed on my home computer, so I can't test but I thik you need something like:
oExcel.ActiveSheet.Cell(11,22).Formula = "=SUM(K19;K16;K10;K7)"
But again, this is didn't tested.