Richard:
So you only have jpg files on those CDs, right? There are no other data files, album folder, etc. in there.
I copied all my albums and images from CD back up into iPhoto5.
By that do you mean you dragged them from the CDs into the open iPhoto window? If you dragged them into the iPhoto Library folder then that's the wrong way to do it. You must import the image files into iPhoto from outside the iPhoto Library folder. Along those lines here are two Apple KB documents that you should be aware of, particularly the second one:
iPhoto Library Description
Don't tamper with files in the iPhoto Library folder from the Finder
What happened to your original iPhoto 4 library folder? Do you still have it intact? If you do then you can place it in your Pictures folder, launch iPhoto 5 and it will find it and tell you it needs to convert the library to version 5. Once done you should have your library converted you'll have everything back up and running, including the albums, rolls, keywords, etc.