Invalid network name in tree connect...

[smb]

If i try to connect to a samba share using smbclient, i get the following 
(names and such changed for security reasons):

su-2.03# ./smbclient '\\archive\backup\' -I 209.73.30.69 -U username
Added interface ip=###.###.###.### bcast=###.###.###.### 
nmask=255.255.255.192
Password: 
Domain=[DOMAINNAME] OS=[Unix] Server=[Samba 2.0.5a]
tree connect failed: ERRSRV - ERRinvnetname (Invalid network name in tree
connect.)

if I try to connect from an NT box, it says that I'm not authorized to
logon from that workstation.

what's going on, and how should I remedy this?

thanks in advance.

--Brian J. Cohen
  Intercarve Networks