Currently your code inside /kernel/user.php looks like:
if ($user->isNew()) {
$uid = $this->db->genId($this->db->prefix('users').'_uid_seq');
$sql = sprintf("INSERT INTO %s (user_uni, user_grade) VALUES (%s, %s)", $this->db->prefix('user_uni'), $uid, $this->db->quoteString('user_grade'));
} else {
$sql = sprintf("UPDATE %s SET user_uni = %s, user_grade = %s", $this->db->prefix('user_uni'), $this->db->quoteString('user_grade'));
}
but I believe you should have changed it to something like:
if ($user->isNew()) {
$uid = $this->db->genId($this->db->prefix('users').'_uid_seq');
$sql = sprintf("INSERT INTO %s (uid, uname, name, email, url, user_avatar, user_regdate, user_icq, user_from, user_sig, user_viewemail, actkey, user_aim, user_yim, user_msnm, pass, posts, attachsig, rank, level, theme, timezone_offset, last_login, umode, uorder, notify_method, notify_mode, user_occ, bio, user_intrest, user_mailok, user_uni, user_grade) VALUES (%u, %s, %s, %s, %s, %s, %u, %s, %s, %s, %u, %s, %s, %s, %s, %s, %u, %u, %u, %u, %s, %.2f, %u, %s, %u, %u, %u, %s, %s, %s, %u, %s, %s)", $this->db->prefix('users'), $uid, $this->db->quoteString($uname), $this->db->quoteString($name), $this->db->quoteString($email), $this->db->quoteString($url), $this->db->quoteString($user_avatar), time(), $this->db->quoteString($user_icq), $this->db->quoteString($user_from), $this->db->quoteString($user_sig), $user_viewemail, $this->db->quoteString($actkey), $this->db->quoteString($user_aim), $this->db->quoteString($user_yim), $this->db->quoteString($user_msnm), $this->db->quoteString($pass), $posts, $attachsig, $rank, $level, $this->db->quoteString($theme), $timezone_offset, 0, $this->db->quoteString($umode), $uorder, $notify_method, $notify_mode, $this->db->quoteString($user_occ), $this->db->quoteString($bio), $this->db->quoteString($user_intrest), $user_mailok,$this->db->quoteString($user_uni), $this->db->quoteString($user_grade);
} else {
$sql = sprintf("UPDATE %s SET uname = %s, name = %s, email = %s, url = %s, user_avatar = %s, user_icq = %s, user_from = %s, user_sig = %s, user_viewemail = %u, user_aim = %s, user_yim = %s, user_msnm = %s, posts = %d, pass = %s, attachsig = %u, rank = %u, level= %u, theme = %s, timezone_offset = %.2f, umode = %s, last_login = %u, uorder = %u, notify_method = %u, notify_mode = %u, user_occ = %s, bio = %s, user_intrest = %s, user_mailok = %u, user_uni = %s, user_grade = %s WHERE uid = %u", $this->db->prefix('users'), $this->db->quoteString($uname), $this->db->quoteString($name), $this->db->quoteString($email), $this->db->quoteString($url), $this->db->quoteString($user_avatar), $this->db->quoteString($user_icq), $this->db->quoteString($user_from), $this->db->quoteString($user_sig), $user_viewemail, $this->db->quoteString($user_aim), $this->db->quoteString($user_yim), $this->db->quoteString($user_msnm), $posts, $this->db->quoteString($pass), $attachsig, $rank, $level, $this->db->quoteString($theme), $timezone_offset, $this->db->quoteString($umode), $last_login, $uorder, $notify_method, $notify_mode, $this->db->quoteString($user_occ), $this->db->quoteString($bio), $this->db->quoteString($user_intrest), $user_mailok, $uid),$this->db->quoteString($user_uni), $this->db->quoteString($user_grade));
}
NOTE: I didn't test this code to verify it works so please check it closely - and as always
MAKE A BACKUP OF EVERYTHING BEFORE YOU ATTEMPT NEW CODE.
The idea here is that the original code created (or updated) the user record fields. Your code did not create all the fields - including your new ones. I'm surprised you didn't get a SQL error. Make sure when you're writing/debugging new code to turn on XOOPS debug in Admin.