Trouble Joining NT domain

[Rick Wozencraft]

I just received a NAS server which has RedHat 6.1 and Samba 2.0.6
Our NT domain name is hpinc

smb.conf 
	workgroup = hpinc
	NetBios name = hpnas1
	Security = domain
	Encrypt Passwords = yes
	Password Server = hppdc
	Wins Server = hppdc

I have updated the lmhosts file with the entry for the hppdc

when I try to run:      smbpasswd -j hpinc -r hppdc

I get the following:
cli_net_auth2:Error NT_STATUS_ACCESS_DENIED
cli_nt_setup_creds: auth2 challenge failed
modify_trust_password: unable to setup the PDC credentials to machine HPPDC.
Error was: NT_STATUS_ACCESS_DENIED
change_trust_account_password: Failed to change password for domain HPINC
Unable to join domain HPINC