Run Time Error 9 " Script out of range

The error is not on this line

  Set rng = Sheets("Purchase Order").Range("B15:L34")

More likely on these two lines

Set wkb = Workbooks.Open("D:\Purchase Order Data\Purchase Order Data.xlsb", Password:="vv2325", WriteResPassword:="vv2325")
  Set wks = wkb.Sheets("PO Data")