smb.conf security issue

[sk_tech101 at yahoo.com]

Hello, 

I am hitting issue following issue. I think I should not need realm, can anyone help? 

root at jut[12]###/mail/product/samba/bin/net rpc join -I 10.1.3.50 -S DEVWIN -U "administrator%home"Failed to join domain: Invalidconfiguration ("realm" set to '', should be 'devwin2k.com') andconfiguration modification was not requested 
My smb.conf
workgroup=devwin2k#workgroup=
#realm=
netbios name=goodguy
password server=10.1.3.250
#password server=
security=domain
#security=ADS
#kerberos method = system keytab
winbind uid=10000-20000
winbind gid=10000-20000
winbind use default domain=yes
winbind separator=:
max log size=50000
wins server=

Thanks!