I've been getting this error on a shared photostream that is private. I keep getting a message stating "Resource Unavailable" after it attempts to load for a few minutes.
It did work in the past because I know some family members said they did see the video, but now nobody can attempt to watch the video on iOS devices. Windows and Mac OS still works, but it may be because those devices will copy the video locally to a temp folder on the hard disc and play from there.
I also noticed that Photostream has limits for how many photos can be viewed in an hour, and in an entire day:
http://support.apple.com/kb/HT4858
- Maximum combined number of photos and videos to share per hour: 1000
- Maximum combined number of photos and videos to share per day: 10,000
I don't think i've had over 10,000 plays on the video but who knows....