OpenVPN connected to firewall. Now what?

Let me clarify, sorry. I've also made headway and can fill in more details.

I want clients to be able to tunnel in and access a shared folder. Some are Active Directory, others are not.

The setup is like this

smoothwall-->sbs server 2003-->xp computer
                                                -->NAS

I'm fine with having the shared folder on the server, I only mention those other two devices as options.

I am on a Mac using Tunnelblick. I can connect just fine.

I can ping the server, 192.168.0.2. I can even RDC to that address!

I set up a shared folder on the server, we'll call it MyShare, on F:Data. I went to sharing and security and selected "Share this Folder". There are other tabs if I right-click, such as "Web Sharing" but I haven't done anything with that or other options.

On my Mac, following instructions I found on apples website, if I try to go to smb://192.168.0.2/MyShare, I get "Connection Failed. There was an error connecting to the server. Check the server name or IP address and try again...." If I click okay, the connecting to server status box changes to: "could not connect to the server because the name or password is not correct. Try Again / Cancel"

Thanks for the help.

In my more verbose description I failed to state that I am using the Zerina openVPN mod on the smoothwall.

I do not have a password or a username. There are only a handful of sbs 2003 licensed users. The rest of the users are not.

the \\serverIP\share doesn't seem to work on Mac. I can see the Mac appending it to look like this: afp:// \\serverIP\share.

I got help from another source who said the problem was that the subnets inside the network weren't matching. Will post again once I get that sorted out.