Mount Win2K shares from a Linux Client.

Here’s the scenario:
mount -t smbfs //machinename/sharename /mountpoint

In one domain:
Works OK for shares on one win 2K server. (Exch 2K, SQL, IIS)
Does Not work for shares on another server (DC).

In another domain:
No shares will mount. The server in this case is just a plain vanilla Win 2K file server — used a just that — a respository of files and apps.

Each failure yields the ERRDOS: ERRnoaccess message.
And, I can ping by name to/from any machine on the network.

no password encryption.
How obvious is that which I’m missing, here?