Excel stürzt nach Klick ab :(

Private Sub cmd_Start_Click()
Dim A As Range
Dim B As Range
Dim C As Range
Dim AZ As Integer
AZ = Range("A65536").End(xlUp).Row
For Each A In Range("C2:C" & AZ)
If A.Value <> "" And A.Offset(0, 1).Value <> "" Then
A.Offset(0, 2).Value = A.Value & "-" & A.Offset(0, 1).Value
End If
Next
For Each B In Range("B2:B" & AZ)
If B.Value <> "" And B.Offset.Value <> "" Then
B.Offset(0, 4).Value = "=RC[-4]&MID(""MoDiMiDoFrSaSoGu"",WEEKDAY(VALUE(RC[-4]&R1C6),2)*2-1,2)"
End If
For Each C In Range(ActiveSheet.UsedRange.Address)
If C.Text = "#WERT!" Then Range(C.Address) = "32Gu"
Next
Next
End Sub