The hi res files are encoded using MPEG 2 and will require the MPEG 2 codec by installed on your system in order to view them. Mac users and folks not using Windows Vista Ultimate should have a look at the free VLC media player in order to view the files and play them as your desktop wallpaper.
Helpful Links
This page has instructions on how to set up VLC to play animations on your desktop.
Alternatively, Apple sells a $19.95 add-on for Quicktime which will play MPEG2.
Ultimately, these files were created for use with "Dreamscene" (a feature of Windows Vista "Ultimate") but may be compatibile with other systems. I hope to add more animations as time permits.