The PPM Key Structure File is in Comma Separated Values (CSV) format. If you open this file directly using Microsoft Excel (which may be your default application for opening CSV files), the application by default applies the General format to all the values in the file, reformatting any values beginning with zeros by removing those leading zeros. For example, a value of 00101 in the CSV file will appear as 101 in the Excel spreadsheet layout.
To avoid this:
Refer to Microsoft's Help for your particular version of Excel.