SQL-DATABASE ERROR

Database error in WoltLab Burning Board: Invalid SQL: INSERT LOW_PRIORITY INTO bb10_sessions VALUES ('','0','38.107.179.214','CCBot/1.0 (+http://www.commoncrawl.org/bot.html)','1328387120','forgotpw.php','0','0','0')
mysql error: Duplicate entry '' for key 'PRIMARY'
mysql error number: 1062
Date: 04.02.2012 @ 21:25
Script: /forgotpw.php
Referer: