Can anyone tell me why this works on the active sheet instead of the "Centre System Export" sheet?

With Worksheets("Centre System Export")
        .Unprotect ("passwd")
        Set rBottomCell = Cells(65536, 5)
        If IsEmpty(rBottomCell) Then
            Set rBottomCell = rBottomCell.End(xlUp)
            ' Cater for the scenario where the the worksheet contains no data.
            If rBottomCell.Rows.Row < 5 Then Exit Sub
        End If
        .Range("E5", Range("E5", rBottomCell).Offset(0, 29)).ClearContents
        .Protect ("passwd")
End With