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 ('ac1e9b07bddd79b78375bdc80404b023','0','38.107.191.96','CCBot/1.0 (+http://www.commoncrawl.org/bot.html)','1280599764','Blasensprung.htm','0','0','', 'F')
mysql error: Duplicate entry 'ac1e9b07bddd79b78375bdc80404b023' for key 'PRIMARY'
mysql error number: 1062
mysql version: 5.1.47
php version: 5.3.2
Date: 31.07.2010 @ 20:09
Script: /Lexikon/Blasensprung.htm
Referer: