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.
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.