Makro setzt Filter manchmal erst ab Zeile 2 anstat

Sub Datei_B1_FilternUndDrucken()
Dim ws As Worksheet, z As Long, i As Long, aWerte(), weiter As Integer
Workbooks.Open Filename:= _
"F:\Datenschnittstellen\ATOMIG\Master KAG\Daten\Orderimport\swift\Mailsendung\AUTO_B1. _
xls"
Sheets("MT304").Activate
Set ws = ActiveWorkbook.ActiveSheet
ReDim aWerte(0)
For z = 2 To ws.Cells(ws.Rows.Count, 1).End(xlUp).Row
If fWertInArray(aWerte, ws.Cells(z, 1).Value) = False Then
ReDim Preserve aWerte(UBound(aWerte) + 1)
aWerte(UBound(aWerte)) = ws.Cells(z, 1).Value
End If
Next
For i = 1 To UBound(aWerte)
ws.Range("A1").AutoFilter Field:=1, Criteria1:=aWerte(i)
ws.PrintOut
Next
ws.Range("A1").AutoFilter Field:=1
ActiveWorkbook.Save
End Sub

Function fWertInArray(aWerte, Wert) As Boolean
Dim i As Long
For i = LBound(aWerte) To UBound(aWerte)
If aWerte(i) = Wert Then
fWertInArray = True
Exit Function
End If
Next
End Function

Viele Grüße
Ralf