Subscript out of range

Sub Auswertung()
Dim wksQ As Worksheet   'Quelltabelle
Dim wksZ As Workbook    'Zieltabelle
Dim rng As Range
Dim lastRow As Long, lRow As Long, lFirst As Long
Dim n As Integer
Set wksQ = Sheets("Sheet1")
Set wksZ = Workbooks("export.xls").Worksheets("Sheet1")
With wksZ.Rows("2:65536")
.ClearContents
.ClearFormats
End With
lRow = 2
lFirst = 2
lastRow = IIf(wksQ.Range("A65536") <> "", 65536, wksQ.Range("A65536").End(xlUp).Row)
For Each rng In wksQ.Range("A2:A" & lastRow)
With rng
.EntireRow.Copy wksZ.Cells(lRow, 1)
If rng.Offset(1, 0) <> rng Then
For n = 5 To 8
wksZ.Cells(lRow + 1, 1) = "Total"
wksZ.Cells(lRow + 1, 1).Font.Bold = True
wksZ.Cells(lRow + 1, n) = "=SUM(R[" & -(lRow - lFirst + 1) & "]C:R[-1]C)"
'wksZ.Cells(lRow + 1, n) = _
'Application.Sum(wksZ.Range(wksZ.Cells(lFirst, n), wksZ.Cells(lRow, n)))
wksZ.Cells(lRow + 1, n).Font.Bold = True
wksZ.Cells(lRow + 1, n).NumberFormat = "#,##0.00"
Next
lRow = lRow + 1
lFirst = lRow + 1
End If
lRow = lRow + 1
End With
Next
End Sub