Some AFP shares not showing when connecting to 10.5.8 server

I have a 10.5.8 server on a dual G5 (fully updated). It has two internal disks - one with system and data and one only with data. Yesterday, with no apparent reason, the data share on the system disk doesn't appear when I try to connect to it (the other share appears and works fine). Both shares has the same setup - only afp sharing with registered users, users connecting via OD (simple sign on), ACL permissions via a group (full control), Posix permissions also via a group (read and write). I have checked disk, repaired permissions, restarted both afp and OD service and rebooted the server, propergated permissions - no change. I have also unshared the folder and shared it again - no change. I have created a test share on the same disk and it does not appear either when connecting to it. Nothing in the Server Admin indicates that anything is wrong. I haven't been able to find any errors in the log. Does anyone have any ideas? TIA, Peter