SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Invalid SQL: INSERT INTO bb1_sessions (sessionhash,userid,ipaddress,useragent,lastactivity,request_uri,styleid,langid,authentificationcode, zone) VALUES ('750e380f886b6f1f2c39060739e050b7','0','38.107.191.97','CCBot/1.0 (+http://www.commoncrawl.org/bot.html)','1280599790','Bericht_IVF.htm','0','0','', 'FI')
mysql error: Duplicate entry '750e380f886b6f1f2c39060739e050b7' for key 'PRIMARY'
mysql error number: 1062
mysql version: 5.1.47
php version: 5.3.2
Date: 31.07.2010 @ 20:09
Script: /Fachinformationen/Bericht_IVF.htm
Referer: