Connection error problem

I was cleaning out my site and somehow I might of erased something and now when I want to go this guestbook I get a connection error. Help.
I would like to upgrade this to the new one.
http://ccgrove.com/atlsfiction/index.php

Check your database info in the config.inc.php file. It looks like it can't find the database password.

admin/config.inc.php file:
http://proxy2.de/forum/viewtopic.php?t=3654

how can I reset it without losing the posting in the book.

You can redownload the guestbook and then overwrite the files on your site with the ones you have downloaded. All the configuration and posts are kept in your mySQL database and so will still be there. You do not need to run the install file again but you will need to edit the config.inc.php file again.