samba - Jan 2004 - smbclient from linux to Win2k3 server AD share

We are trying to mount a dfs share on a Redhat 9 machine that's served
from our W2K3 AD server.  We've been banging our heads against this for
quite a while, so I thought it time to run up the white flag and ask
here.  We've been trying variations of this:

  
# mount -t smbfs -o
username=OURDOMAIN\administrator,password=adminpasswd //servername/dfs
/mnt/dfs

and we've been getting

16162: session setup failed: ERRDOS - ERRnoaccess (Access denied.)
SMB connection failed

We're sure we are using the right password, and we have tried
username=administrator and username=OURDOMAIN\administrator, and we know
that the share name is right (can be browsed to fine from any Windows
client.  

So it's likely that we're not sending the right stuff for
authentication.  We can't browse with smbclient -U administrator -L
servername, we get: tree connect failed: NT_STATUS_ACCESS_DENIED

This is likely something basic, but the two of us here are getting
nowhere with it.  Any pointers of other things I should be trying?

Thanks,
Fran

-- 

Fran Fabrizio
Senior Systems Analyst
Department of Computer and Information Sciences
University of Alabama - Birmingham
fran@cis.uab.edu
(205) 934-0653