Please HELP_ Query Error

I was using "Advanced Guestbook 2.4.1" in my site then I did the steps to upgrade to "Advanced Guestbook 2.4.1" and every thing was good but when I tried to Sign the Guestbook I found this Msg:

Query Error
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MySQL Error : Query Error
Error Number: 1064 You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near 'SET session_id='cab6c4a100c0bd7020365dc715ef372a', validate_key
Date : Wed, June 7, 2006 15:36:06
IP : 82.137.200.18
Browser : Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; (R1 1.5))
Referer : http://www.maynasr.com/guestbook/index.php
PHP Version : 4.3.2
OS : Linux
Server : Apache
Server Name : www.maynasr.com

WOULD YOU ADVICE HOW TO SOLVE THIS ERROR…

THANK YOU IN ADVANCE