Forum Database Error?
 

I recently started having issues with vBulletin 4.2.0. I haven't changed anything to the code or settings so I'm not sure why this started happening.

Any insight and directions to fix are greatly appreciated.

Here's the notification I got as admin:

Database error in vBulletin 4.2.0:

Invalid SQL:

INSERT INTO vb_postlog
(postid, useragent, ip, dateline)
VALUES
(875, 'Opera/9.80 (Windows NT 5.1; U; ru) Presto/2.10.289 Version/12.00', 94687797, 1359671480);

MySQL Error : Duplicate entry '875' for key 'PRIMARY'
Error Number : 1062

When you make a reply and press "post reply" or "post quick reply" an error pops up saying "Database Error." You remain on the post edit page and nothing happens. However if you refresh the page, the post has been made but the thread count hasn't been updated.

Ideas and solutions? Thanks!