samba - Feb 2010 - samba: net rpc join unable to setup creds

Hi experts,

I am getting the error when trying to join samba server into domain.
net rpc join -U user%password

returns with rpccli_netlogon_set_trust_password: - unable to setup creds
<NT_STATUS_ACCESS_DENIED> !

rpc command failed ! <NT_STATUS_ACCESS_DENIED>.

what is the error in smb.conf. i am running samba-3.4.5

Thanks
AP