samba - Oct 2005 - Configuration file error message

I have added the below line to the global section of my smb.conf file.  It 
appears that Samba 3.0.10 is having a problem with this line as it rejects 
it.  I am trying to configure samba so that uses of a Solaris 8.0 server 
will be able to mount shares from our Windows AD environment.

realm = rb.win.frb.org

The error messages that I am getting are 

Unknown parameter encountered: "realm"
Ignoring unknown parameter "realm"

Robert D. Setterlund
Federal Reserve Bank of Boston
600 Atlantic Ave., Boston, MA, 02106
(617) 973-3374
robert.setterlund@bos.frb.org