hp-ux change password

just now i tried to change one user password on hp-ux, but it prompt this instead:

# passwd user
Enter your user number here:

what the hell is this? never seen this before. i tried entered a few number but failed :(

but google helped me out :)
actually the system is in trusted mode. a user has been given admnum
check it with /usr/lbin/getprpw -m admnum user

# /usr/lbin/getprpw -m admnum user
admnum=430

provide the number while changing the password

# passwd user
Enter your user number here: 430
Last successful password change for user: NEVER
Last unsuccessful password change for user: Mon Jun 19 00:40:18 2006

New password:
Re-enter new password:

password changed succesfully!