MySQL appears error:duplicate entry "xxxx" for key 1 solutions

The error is as follows:
discuz! Info:mysql Query Error

User: Love Me Jingmen
Time:2007-3-5 11:00am
Script:/bbs/post.php

Sql:insert into Cd12sb_threads (FID, readperm, Price, iconID, typeID, author, Authorid, subject, Dateline, Lastpost, last Poster, Displayorder, Digest, blogs, special, attachment, subscribed, moderated, supe_pushstatus)
VALUES (' 64 ', ' 0 ', ' 0 ', ' 0 ', ' 0 ', ' Love Me Jingmen ', ' 5 ', ' FG ', ' 1173063640 ', ' 1173063640 ', ' Love Me Jingmen ', ' 0 ', ' 0 ', ' 0 ', ' 0 ', ' 0 ', ' 0 ', ' 0 ' , ' 0 ')
Error:duplicate entry ' 8181 ' for key 1
Errno.: 1062

Similar error has beed dispatched to administrator before.

The MySQL manual was then opened and a description of the tinyint and smallint and int types was found:
tinyint[(M)] [UNSIGNED] [Zerofill]
A very small integer. The signed range is 128 to 127, and the unsigned range is 0 to 255.
smallint[(M)] [UNSIGNED] [Zerofill]
A small integer. The signed range is 32768 to 32767, and the unsigned range is 0 to 65535.
mediumint[(M)] [UNSIGNED] [Zerofill]
A medium sized integer. The signed range is 8388608 to 8388607, and the unsigned range is 0 to 16777215.
int[(M)] [UNSIGNED] [Zerofill]
A normal size integer. The signed range is 2147483648 to 2147483647, and the unsigned range is 0 to 4294967295.
integer[(M)] [UNSIGNED] [Zerofill]
This is a synonym for int.
bigint[(M)] [UNSIGNED] [Zerofill]
A large integer. The signed range is 9223372036854775808 to 9223372036854775807, and the unsigned range is 0 to
18446744073709551615.
I see!
That's why other online invalid query:duplicate entry ' 32767′for key 1 went wrong!

Now we got a way. Upgrade database

ALTER TABLE ' cdb_posts ' change ' pid ' pid ' INT (a) UNSIGNED not NULL DEFAULT ' 0 ' auto_increment;