Try changing password on a HP-UX trusted system and get the followin:
Password cannot be changed. Reason: Cannot access protected password entry.
This means the auth files in /tcb are out of sync with the /etc/passwd file. Someone may be making changes manually to the /etc/password file (like adding user acocunts), but that doesn't update or create the appropriate entries in /tcb/files/auth
check it by running the authck -p (or pwck -s) command to verify the trusted computing base /tcb This doesn't fix the problem, you'll have to delete (from /etc/passwd) and add again (via sam or useradd) or use the pwconv command.