Hi,
I have similar issues with the DNS-323 (firmware 1.08). It worked fine for years and than started all of a sudden.
see also
http://forums.dlink.com/index.php?topic=40886.0When I try to copy files from/to the NAS on any machine, it would fail after a random amount of time giving the following error: "The specified network name is no longer available."
I replaced cables, my router, the disks etc. while windows copy would fail, FTP transfers don't. it almost seems like the NAS is dropping of the network. running both FTP and windows copy at the same time learned me that it's not the complete NAS dropping of the network but only the windows copy stuff (samba) because FTP keeps running fine.
so far I never managed to solve this frustrating issue

Greetz