Updating Windows clients from Linux server

I have installed NOD32 2.51 on Windows XP clients which do not have internet access. I have also installed the Linux file server version 2.06 which uses the nod32_update script to download updates when available. I have set up a mirror folder in /home/public/NOD32/mirror, and all PC's have read/write access to this folder through Windows Explorer.

I have configured the NOD32 clients, adding the server \\servername\public\NOD32\mirror, which for some reason changes all the \'s to /'s. I have set in LAN settings to use the current user account. In the username and password boxes I have also specified the current user's username and password, using the form DOMAIN/user.

When I press Update, nothing happens. In the log file, I get
Time Module Event User
02/02/2006 20:23:30 Update Update attempt failed (Update file download failed.) PAUL\Paul

Any ideas what I'm doing wrong? If you're wondering why I only have 2.06 on the server, it's because the license file doesn't seem to work on 2.51 on Linux. Thanks. Paul