I've just tried adding a record to the Phonebook. I get the following error:

Location : CDatabase/CMySQL::InsertRecord
Message : Insert Record (tbl_clients) : Incorrect integer value: 'AuthSessionKey:(C:\inetpub\wwwroot\Joomla\addbook\staff\app\cls_auth_base.inc.php)' for column 'rlog_create_user_id' at row 1

What could be causing this problem?

>Location : CDatabase/CMySQL::InsertRecord
Message : Insert Record (tbl_clients) : Incorrect integer value:

Uh-oh, it looks like you broke it. I've never encountered the error. I think it's better to start over rather than finding the cause. When you modify the code, back up the code frequently so you can go back to the previous states.