Networked folders won't show in Win Explorer

[swinebird04]

I've got a problem accessing shared folders over a network. I'm running Windows XP SP2 (as are the other computers on my LAN) with no third party firewall. I've got my mp3 collection shared as "\\jacob\music\" The problem is that for two PCs on the LAN, some of the folders within that share don't show up. Here's an example directory tree:

- jacob (computer name)
  - music (shared folder)
    - Jack Johnson (artist)
      - 2005. In Between Dreams (cd title)
        - 01. Better Together.mp3 (and so on for all the tracks...)

Here's the problem: I can view down to the artist folder, but the cd folder doesn't show up; when I double-click on Jack Johnson, I just see an empty directory. If I manually type into the address bar "\\jacob\music\Jack Johnson\2005. In Between Dreams" then I can view and play all the mp3s in that folder (so it's not really an access problem, it's just that I can't *see* the folders), but if I then go Up one level, the "2005. In Between Dreams" folder still doesn't appear. The other thing is that if I go to the music share folder via the PC's IP address (192.168.1.102) instead of the network name (jacob), then everything *will* be visible. I don't have this problem with every artist in my collection - it's just random ones, and it doesn't seem to be related to when the folder or files were created. Also, the other PC on the LAN doesn't have this problem; all the folders and files are perfectly viewable from it. Can anyone suggest what might be causing this and how to correct it? Thanks!