samba - Dec 2006 - connect to windows 2003 domain share access denied

I've got a linux machine that is on a seperate network from a windows 
2003 domain controller.  I own the linux box and another company owns 
the windows domain server.  They have opened a port between our network 
(445) so that I can connect to a share they made for me.  My question is 
this, is it possible to connect to a share on a windows machine that is 
part of a domain, when my linux machine is not part of the domain?
I have the username and password they setup for me to use on the share, 
but when I try to connect to it, using mount -t smbfs, I get an access 
denied error.
The actual error is this: session setup failed: ERRDOS - ERRnoaccess 
(Access denied.)  Thanks in advance.