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) VALUES ('0a1274948ba8bdd22940842bf554eb90','0','38.107.179.220','CCBot/1.0 (+http://www.commoncrawl.org/bot.html)','1328638565','download.detail49.655.html','0','0','')
mysql error: Duplicate entry '0a1274948ba8bdd22940842bf554eb90' for key 'PRIMARY'
mysql error number: 1062
mysql version: 5.1.47
php version: 5.3.10
Date: 07.02.2012 @ 19:16
Script: /download.detail49.655.html
Referer: