These files are intended to be used with either Creo Elements/Pro 5.0 or Creo 1.0. They are not compatible with any other CAD package and they are not compatible with the "Commercial" edition, Schools only.
You can get details on how to download your own FREE copy of Creo Elements/Pro 5.0 at
http://www.ptc.com/go/firstgettingstarted.