cdr_mysql.c:342 mysql_log: Failed to insert into database

I have this error … per 1 min.

[Aug 18 18:36:43] ERROR[24334][C-0001dd59]: cdr_mysql.c:342 mysql_log: Failed to insert into database: (1062) Duplicate entry '1408354531' for key 'uniqueid'
mysql> desc cdr
    -> ;
+-------------+--------------+------+-----+-------------------+----------------+
| Field       | Type         | Null | Key | Default           | Extra          |
+-------------+--------------+------+-----+-------------------+----------------+
| uniqueid    | int(11)      | NO   | PRI | NULL              | auto_increment |
| time        | timestamp    | NO   |     | CURRENT_TIMESTAMP |                |
| calldate    | datetime     | NO   | MUL | NULL              |                |
| clid        | varchar(80)  | NO   |     | NULL              |                |
| src         | varchar(80)  | NO   | MUL | NULL              |                |
| dst         | varchar(80)  | NO   | MUL | NULL              |                |
| dcontext    | varchar(80)  | NO   |     | NULL              |                |
| channel     | varchar(80)  | NO   |     | NULL              |                |
| lastapp     | varchar(80)  | NO   |     | NULL              |                |
| lastdata    | varchar(80)  | NO   |     | NULL              |                |
| duration    | int(11)      | NO   |     | NULL              |                |
| billsec     | int(11)      | NO   |     | NULL              |                |
| disposition | varchar(45)  | NO   |     | NULL              |                |
| amaflags    | int(11)      | NO   |     | NULL              |                |
| accountcode | varchar(20)  | NO   | MUL | NULL              |                |
| userfield   | varchar(255) | NO   |     | NULL              |                |
+-------------+--------------+------+-----+-------------------+----------------+

this is my cdr…

AND MY cdr_mysql.conf file.

[global]
hostname=localhost
dbname=asteriskrealtime
table=cdr
password=mypassword
user=root
port=3306

[columns]
alias start => calldate

why this error happens…? and how I can fix it?

Simplify your dialplan so that no more than one CDR is generated per call leg, or include more than uniqueid in the primary key.