Problem with validation in Excel

Question

I have this code:

Private Sub OptionButton1_Click()

  If OptionButton1.Value = True Then

    Application.EnableEvents = False
    Application.DisplayAlerts = False
    ActiveSheet.Unprotect ("ALS rules!")

       With ActiveWorkbook.ActiveSheet.Range("A18:A1269").Validation
        .Delete
        .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:=xlBetween, Formula1:="1,2,3"
        .IgnoreBlank = True
        .InCellDropdown = True
        .InputTitle = "Options"
        .ErrorTitle = ""
        .InputMessage = "Choose from list:"
        .ErrorMessage = ""
        .ShowInput = True
        .ShowError = True
        End With

    [B16] = "Master function"
    [I16] = "Related component"

    Application.EnableEvents = True
    Application.DisplayAlerts = True
    ActiveSheet.Protect AllowSorting:=True, AllowFiltering:=True, _
        AllowUsingPivotTables:=True, DrawingObjects:=True, Contents:=True, Scenarios:=True, Password:="ALS rules!"

  End If
End Sub

But I get the error message: The object invoked has disconnected from its clients. And it seam to be this line which is the problem:

.Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:=xlBetween, Formula1:="1,2,3"

Does anyone have an idea of what could be the problem?

/ David