Copied iphoto library to new 10.7.3 Air. Now 10.6.8 iphoto not working

Question

Hello,
I recently purchased a new Macbook Air, running 10.7.3. I copied my iphoto library through file sharing from my previous MacBook Pro running 10.6.8. I have the photos on the new machine, so they're safe. I went back to delete them on the Pro, since I'll be handing it off to my wife. But iphoto will not open, says "You have made changes to your photo library using a newer version of iPhoto. Please quit and use the latest version of iPhoto."
Two questions:
1. How do I get the version of iphoto they're requesting? If I have to buy it, I'm sorry but I already purchased it once.
2. Is it possible to reinstall just iphoto in it's previous version instead?
Thanks.

Answer 1

Try the following:
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 Mt. Lion from the User/Library/Containers/com.apple.iPhoto/
Data/Library/Caches/com.apple.iPhoto folder
3 - launch iPhoto and try again.
NOTE: 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