General Error after login to ACP

When I try to login to the Admin Control panel I see this error message :

General Error
SQL ERROR [ mysql4 ]

Duplicate entry '5271' for key 1 [1062]

SQL

INSERT INTO phpbb_log (user_id, log_ip, log_time, log_operation, log_data, log_type) VALUES (2, 'my_ip_address', 1227347918, 'LOG_ADMIN_AUTH_SUCCESS', '', 0)

BACKTRACE

FILE: includes/db/mysql.php
LINE: 158
CALL: dbal_mysql->sql_error()

FILE: includes/functions.php
LINE: 2664
CALL: dbal_mysql->sql_query()

FILE: includes/functions.php
LINE: 2271
CALL: add_log()

FILE: adm/index.php
LINE: 33
CALL: login_box()

Please help, I hope this is not the end of my forum