Photo Stream automatic import not working

Question

I previously just had an iPhone and iMac. When I added photos to either device, they uploaded to iCloud and appeared on both. When I did this from my iPhone to my iMac, it worked fine, and my iMac automatically imported the photos from my Photo Stream to my library.
I just got the new MacBook Air. I transferred my iPhoto Library through Finder. Everything works fine. When I add a photo from my iPhone to Photo Stream, it appears on the Photo Stream on both of my Macs and both automatically import it. However, if I add a photo to either of my Macs, the other Mac does not automatically import it, and instead, I need to manually import it each time.
How can I fix this so my Macs automatically import the photos? I have the appropriate settings enabled.
To clarify, the photos appear in the "Photo Stream" section correctly, they just do not import to my library automatically, and I need to manually import them.

Answer 1

Give this a try:
1 - delete the iPhoto preference file, com.apple.iPhoto.plist, that resides in your
     User/Home/Library/ Preferences folder.
2 - delete iPhoto's cache file, Cache.db, that is located in your
User/Home/Library/Caches/com.apple.iPhoto folder (Snow Leopard and Earlier).
or with Lion and Mt. Lion from the User/Library/Containers/com.apple.iPhoto/
Data/Library/Caches/com.apple.iPhoto folder
3 - launch iPhoto, reset all of its preferences and try again.
NOTE 1: If you're moved your library from its default location in your Home/Pictures folder you will have to point iPhoto to its new location when you next open iPhoto by holding down the Option key when launching iPhoto.  You'll also have to reset the iPhoto's various preferences.
NOTE 2:  In Lion and Mountain Lion the Library folder is now invisible. To make it permanently visible enter the following in the Terminal application window: chflags nohidden ~/Library and hit the Enter button - 10.7: Un-hide the User Library folder.
OT