Q: Why can't I view my shared photo stream album?

I created an album with about 100 photos in it, and sent it to a few friends, who all imediately accepted the invite.  Then one friend commented on a photo, I clicked on the alert, and nothing showed up.  The photo stream looks empty and grey, like no photos were added, but she commented on something.  What could be the problem here, and how do I fix it?  Thanks!