adding field to advance guestbook 2.2

Hello, I need help adding a field in the advance guestbook. I already added the new field in the mysql. called "last" right below "name" I think I changed all the files but evidently not because it's not recording it on the database nor is it showing up on the index page.

So far I made the changes to addentry.php, entry.php, and form.php. Is there another file that I am forgeting to ad to to make this record to the database?

Thanks, Jason

Make ammendment to lib/gb.class