Makro läuft nicht unter Excel 97 !!!!

Sub selektieren()
Dim lz As Long, i As Long, c As Integer
Dim ws As Worksheet
Set ws = ActiveSheet
lz = Range("A65536").End(xlUp).Row
c = 0
Application.ScreenUpdating = False
Do
For i = 1 To lz
If Cells(i, 1) = 10000 Or i = lz Then
Rows("1:" & i).Cut
Sheets.Add After:=Sheets(Sheets.Count)
c = c + 1
ActiveSheet.Name = "Teil " & c
ActiveSheet.Paste
[A1].Select
ws.Select
Rows("1:" & i).Delete Shift:=xlUp
lz = Range("A65536").End(xlUp).Row
Exit For
End If
Next i
Loop While lz > 1
Application.ScreenUpdating = True
End Sub