I installed iPhoto Library Upgrader on both machines
Yes, I chose the transfered library by pressing "Choose Library".
You only need the iPhoto Library upgrader, if you want to open the library in the current version, iPhoto '11. If your current version is iPhoto '09, as you are saying, you do not need it. But for a new Mac with iPhoto '11 you will need to upgrade any iPhoto'07 libraries.
. I opened iPhoto and "switched to" the imported library. It opens but there are no files in it. I know the original file that was transfered is 50G.
Your screenshot is showing an empty, new iPhoto library. And that iPhoto Library simply cannot be an iPhoto '09 library. Just look at the icons in the library source list. These gray icons have been introduced with iPhoto '11, version 9.3 or later. We need to get the version numbers straight. When iPhoto is running on your MacBook, is the Dock icon blue/cyan or sunset-coloured? What version number are you seeing in the About panel "iPhoto > About iPhoto"?
If you are really runnin iPhoto '11, try to open your transferred library by selecting it directly and double clicking it.
Do you by any chance have two iPhoto versions on your MacBook?
I hope, LarryHN is still following this thread and can help, with getting the versions sorted . I have only the most recent iPhoto '11, version 9.5.1 available for testing.