Realmente este no es un problema de bases de datos, sino de phpbb, pero en la instrucción incial que has puesto hay un error: sobra la , final en la relación de campos.
INSERT INTO phpbb_users (user_id, username, user_regdate, user_password, user_email, user_icq, user_website, user_occ, user_from, user_interests, user_sig, user_sig_bbcode_uid, user_avatar, user_avatar_type, user_viewemail, user_aim, user_yim, user_msnm, user_attachsig, user_allowsmile, user_allowhtml, user_allowbbcode, user_allow_viewonline, user_notify, user_notify_pm, user_popup_pm, user_timezone, user_dateformat, user_lang, user_style, user_level, user_allow_pm, user_country, user_active,
user_actkey,) VALUES (32, 'prueba', 1134492106, '3d186804534370c3c817db0563f0e461', '
[email protected]', '', '', '', '', '', '', '', '', 0, 0, '', '', '', 1, 1, 1, 1, 1, 0, 1, 1, 0, 'D M d, Y g:i a', 'spanish', 2, 0, 1, 0, '02373d51c97d0309')
Un saludo.