I do not know if anyone ever runs into this issue anymore, but the Apple Engineers helped me fix this recently.
They had me do the following:
Turn off Photo Stream in your user account:
Quit iPhoto
Goto System Preferences > iCloud > Uncheck Photo Stream.
Close System Preferences
Then deleting the entire ~/Library/Application Support/iLifeAssetManagement/ directory.
Open Terminal and type in cd Library
then type open . (open space period)
navigate to Application Support and delete the iLifeAssetManagement folder.
quit terminal
Then turn photo stream back on in their photo library.
open iPhoto and click on Photo stream in the left column.
enable photo stream.
It will take some time to download the cached photos but this resolved my problem of having 0 display and no photos in the "My Photo Stream" area when any of my other devices showed new photo stream photos without any problems.