Database Error when I try to add new thread?

[ChEckM@tE]

Hi


I face this error message when I try to add new thread


Database error in vBulletin 3.7.6:

Invalid SQL:
INSERT INTO post
(showsignature, allowsmilie, username, userid, title, pagetext, iconid, visible, dateline, ipaddress, attach, threadid)
VALUES
(1, 1, 'XXXXX', 1, 'XXXXX', 'XXXXX', 0, 1, 1258503483, '87.84.140.68', 0, 64838);

MySQL Error : Duplicate entry '765099' for key 1
Error Number : 1062
Request Date : Wednesday, November 18th 2009 @ 03:18:03 AM
Error Date : Wednesday, November 18th 2009 @ 03:18:04 AM
Script : http://www.XXXXXX/vb/newthread.php?do=postthread&f=20
Referrer : http://www.XXXXXX/vb/newthread.php?do=newthread&f=20
IP Address :
Username :
Classname : vB_Database
MySQL Version : 5.0.81-community






How can I solve it?
Is it servers problem ?



thanks