error when user invokes smbpasswd

[rjlabutis at ensign-bickfordind.com]

hpux306:/usr/local/samba/bin $ ./smbpasswd
Old SMB password:
New SMB password:
Retype new SMB password:
./smbpasswd: machine 127.0.0.1 rejected the session request. Error was :
code 131.

This is the message they get. What causes this problem.
O/S is HP/UX 10.20 with NIS