For the latest video (large), You will need Divx codec.
You can download it directly here or at the following address:
http://www.commentcamarche.net/telecharger/telecharger-74-divx-codecs

For other videos (small), You will need the drive Quicktime.
You can download it directly here or at the following address:
http://www.apple.com/quicktime/download/