Error on 'net ads join'-Failed to set password for machine account (NT

[sapal]

Hello.

I am trying to join a Samba (Version 3.0.23c-1.fc5) to a Active Directory server. I run the command "net ads join -U username" and I get the following error:
Failed to set password for machine account (NT_STATUS_ACCESS_DENIED)
Failed to join domain!

The global setting in my smb.conf is as follows:
[global]

workgroup = Domain Name
server string = Samba Server
security = ads
encrypt passwords = yes
hosts allow = all
password server = *
log file = /var/log/samba/%m.log
max log size = 50
realm = Domain.Com
dns proxy = no


Kindly guide!

Thanks and Regds
Sapna