They gave you bum advice. To upgrade a library to a new version all that is needed is to open that library with the new application and it will be converted on the fly. Do you still have the backup copy? If so move it into your pictures folder (move the current one to the Desktop) and launch iPhoto. It will open and convert the library.
Thanks again for your advice and help. As it turns out, the old original photos were there in another place. But there were separate events with just the thumbnails, and that was what i had been looking at. So that's what must have happened when i did the import incorrectly. i'm going to delete those thumbnails, just to avoid confusion in the future.