Ok, fixed the issue regarding 'Unable to add user to database'
In smf_login.php change line 61
from:
$query="INSERT INTO smf_members (`id_member`, `member_name`, `date_registered`, `posts`, `id_group`, `lngfile`, `last_login`, `real_name`, `instant_messages`, `unread_messages`, `new_pm`, `buddy_list`, `pm_ignore_list`, `pm_prefs`, `mod_prefs`, `message_labels`, `passwd`, `openid_uri`, `email_address`, `personal_text`, `gender`, `birthdate`, `website_title`, `website_url`, `location`, `icq`, `aim`, `yim`, `msn`, `hide_email`, `show_online`, `time_format`, `signature`, `time_offset`, `avatar`, `pm_email_notify`, `karma_bad`, `karma_good`, `usertitle`, `notify_announcements`, `notify_regularity`, `notify_send_body`, `notify_types`, `member_ip`, `member_ip2`, `secret_question`, `secret_answer`, `id_theme`, `is_activated`, `validation_code`, `id_msg_last_visit`, `additional_groups`, `smiley_set`, `id_post_group`, `total_time_logged_in`, `password_salt`, `ignore_boards`, `warning`, `passwd_flood`, `pm_receive_from`) VALUES (NULL, '$username', '$date', '', '0', '', '', '$username', '0', '0', '0', '', '', '0', '', '', '$passwd', '', '$email', '', '0', '', '', '', '', '', '', '', '', '0', '1', '', '', '0', '', '1', '0', '0', '', '1', '1', '0', '2', '', '', '', '', '0', '1', '', '0', '', '', '4', '0', '$salt', '', '0', '', '1')";
to:
$query="INSERT INTO smf_members (`id_member`, `member_name`, `date_registered`, `posts`, `id_group`, `lngfile`, `last_login`, `real_name`, `instant_messages`, `unread_messages`, `new_pm`, `buddy_list`, `pm_ignore_list`, `pm_prefs`, `mod_prefs`, `message_labels`, `passwd`, `openid_uri`, `email_address`, `personal_text`, `gender`, `birthdate`, `website_title`, `website_url`, `location`, `icq`, `aim`, `yim`, `msn`, `hide_email`, `show_online`, `time_format`, `signature`, `time_offset`, `avatar`, `pm_email_notify`, `karma_bad`, `karma_good`, `usertitle`, `notify_announcements`, `notify_regularity`, `notify_send_body`, `notify_types`, `member_ip`, `member_ip2`, `secret_question`, `secret_answer`, `id_theme`, `is_activated`, `validation_code`, `id_msg_last_visit`, `additional_groups`, `smiley_set`, `id_post_group`, `total_time_logged_in`, `password_salt`, `ignore_boards`, `warning`, `passwd_flood`, `pm_receive_from`) VALUES (NULL, '$username', '$date', '0', '0', '', NULL, '$username', '0', '0', '0', '', '', '0', '', '', '$passwd', '', '$email', '', '0', NULL, '', '', '', '', '', '', '', '0', '1', '', '', '0', '', '1', '0', '0', '', '1', '1', '0', '2', '', '', '', '', '0', '1', '', '0', '', '', '4', '0', '$salt', '', '0', '', '1')";