Oracle conversion bug: unique constraint violated

SQL ERROR [ oracle ]

ORA-00001: unique constraint (MYDB.PK_PHPBB_USERS) violated [1]

SQL

INSERT INTO phpbb_users (username, username_clean, user_password, user_pass_convert, user_email, user_email_hash, group_id, user_type, user_permissions, user_timezone, user_dateformat, user_lang, user_style, user_allow_pm, user_actkey, user_ip, user_regdate, user_passchg, user_inactive_reason, user_inactive_time, user_lastmark, user_lastvisit, user_lastpost_time, user_lastpage, user_posts, user_dst, user_colour, user_occ, user_interests, user_avatar, user_avatar_type, user_avatar_width, user_avatar_height, user_new_privmsg, user_unread_privmsg, user_last_privmsg, user_message_rules, user_full_folder, user_emailtime, user_notify, user_notify_pm, user_notify_type, user_allow_viewonline, user_allow_viewemail, user_allow_massemail, user_sig, user_sig_bbcode_uid, user_sig_bbcode_bitfield) VALUES ('AdsBot [Google]', 'adsbot [google]', '', 0, '', '00', 18, 2, '', 0, 'd.m.Y G:i', 'ru', 1, 1, '', '', 1182256727, 1182256727, 0, 0, 1182256727, 0, 0, '', 0, 0, '9E8DA7', '', '', '', 0, 0, 0, 0, 0, 0, 0, -3, 0, 0, 1, 0, 1, 1, 0, '', '', '')

BACKTRACE

FILE: includes/db/oracle.php

LINE: 322

CALL: dbal->sql_error()

FILE: includes/functions_user.php

LINE: 231

CALL: dbal_oracle->sql_query()

FILE: includes/functions_convert.php

LINE: 1839

CALL: user_add()

FILE: install/install_convert.php(1624) : eval()'d code

LINE: 2

CALL: add_bots()

FILE: install/install_convert.php

LINE: 1624

CALL: eval()

FILE: install/install_convert.php

LINE: 799

CALL: install_convert->jump()

FILE: install/install_convert.php

LINE: 203

CALL: install_convert->convert_data()

FILE: install/index.php

LINE: 359

CALL: install_convert->main()

FILE: install/index.php

LINE: 231

CALL: module->load()

DDL Script for Sequence PHPBB_USERS_SEQ:

CREATE SEQUENCE phpbb_users_seq

  INCREMENT BY 1

  START WITH 81

  MINVALUE 1

  MAXVALUE 999999999999999999999999999

  NOCYCLE

  NOORDER

  CACHE 20

/