OS 10.4 clients cannot access Shared Mac folder on W2k Server - URGENT

Question

We have a network of about 25 computers, 10 or so of them are Mac OS 10.4, the rest are Win XP Pro PCs. We have a server dedicated to file sharing. We basically have one main shared folder called "FILES". This is shared for PCs and Macs. Recently after a restart of the server (for regular maintenance), the Macs could not see the shared Mac volume (FILES), PCs could access the share without a problem. After a few minutes (15 or so) the Macs could all of a sudden see the share and
everything was fine.
However, we just restarted the server again and we're having the same issue again. The difference is, this time, after waiting for a few hours, the Macs still cannot see the Mac Share. The macs connect to the server via TCP/IP, the users use their usernames and passwords and can connect to the server, however, the only volume they see is the Micrsoft UAM volume.
When we created a different folder and shared it (through MMC), the Macs could see and access that one.
We get an Event ID 12061 in the System Event Log as the user tries to connect to the share. I found a Microsoft KB article, but no solution to the problem was given. http://support.microsoft.com/kb/q136300/
Here are some things I have tried to remedy the issue, please keep in mind we cannot change the name of the share (FILES) becuase of the thousands of file mappings in quark, etc.:
Again Restarted Server
Stopped Sharing the folder, then reshared it
Stopped sharing the folder
Uninstalled / Reinstalled Appletalk Protocol from network adapter
Uninstalled / Reinstalled File Services for Macintosh [Restarted]
Uninstalled / Reinstalled Appletalk Protocol from network adapter again [Restarted]
Reshared the folder
Created a new mac share called TEST (Macs could see and access)
Moved data from Files to TEST, now Macs could not see TEST
Moved data back to FILES
Created a folder called FILES2, moved data from FILES to FILES2
Stopped sharing FILES (PC and Mac), renamed FILES to FILES1
Renamed FILES2 to FILES (Macs could not see volume)
It seems as though the problem is with an individual file or two, which sort of corresponds the what Microsoft has written regarding the error.
Has anyone had any experience with this issue? Any insight or solution to this issue is greatly appreciated.
Thank you!

Answer 1

It's very important to be as specific as possible when discussion network service access. In your question, it sounds like you want the macs to attach to FILES using SMB/CIFS, but you also call it a Mac share, so it's not obvious if you mean an AFP share or just a share for Macs to use.
You should know that the Macs can connect to either AFP or SMB volumes, and they can browse for SMB over TCP/IP and AFP over both TCP/IP and Appletalk (Appletalk must be turned on and browsing active in Directory Access).
Connecting via SMB to a volume hosted on Windows2K or higher server will fail with the default settings, which require secure connections not supported by Mac OS X (because Samba doesn't support it). To overcome that problem, see this article:
http://www.macosxhints.com/article.php?story=20030922153448490&query=-5000
(scroll down to one of the top-level replies, which explains in detail how to deactivate secure connections)
You might also be able to improve reliability by editing the SMB settings in Directory Access and setting a WINS server, but it depends on your network.