I have started having problems connecting to my 10.4 server SMB shares across the internet. Trying to connect via the finder (Apple+K), it does nothing for about 5 minutes, then gives me the following error: "The finder cannot complete the operation because some data in "smb://xx.xxx.xxx.xxx/" could not be read or written. (Error code -36)."
Local users (same subnet) can connect via smb. I'm just having this problem across the internet. I don't think it's a firewall issue: temporarily disabling the server firewall didn't help.
I can't think of anyone, anywhere who would advocate this setup,
especially since you're enabling guest access, too.
If you really, really, really, really, really need to do it, have you checked your port forwarding on your router? and have you checked with your ISP to see if they have a clue, and if they're actively blocking port 139. Hopefully they are, since that will force you to use a different protocol.
If you need to provide file access to remote users, consider enabling the VPN server built into Mac OS X Server and having the users connect over VPN. That way they appear as a local user, the data transfer is encrypted over the internet and you can control access to the resources.