Status of error #4031268: new

"Duplicate entry 18.116.21.152 for key user_name (INSERT INTO `users` (user_name) \n VALUES (18.116.21.152);)"
"Duplicate entry 18.116.21.152 for key user_name (INSERT INTO `users` (user_name) \n VALUES (18.116.21.152);) from mysql->insert"

Program trace:
#0 /var/www/default/src/main/php/model/user/user.php(414): mysql->insert(user_name, 18.116.21.152, -3)\n#1 /var/www/default/src/main/php/model/user/user.php(222): user->save(-2)\n#2 /var/www/default/http/view_edit.php(44): user->get(-1)\n#3 {main}