"Glad" to hear I'm not alone with this problem.... I've been trying to get the DNS-320 work with OS X for a few days but have a lot of problems with it. I'm running OS X 10.6.6.
I can mount the NAS by SMB in Finder and it is possible to copy files. But when I try to copy a folder with files inside, the folder is created on the NAS but no files. Instead Finder hangs until I force it to quit. Haven't found any solution for this. Also, the browsing on the NAS is very slow with SMB.
I have also tried AFP but this doesn't work well either. With AFP (mounted in "mount server" in finder) it is possible to copy files and folders, at least small folders. I tried copying a few larger filer (around 700mb each) and the copying looked OK until about 50-60% was completed, then suddenly the AFP crashed. Once AFP crashed it is not possible to mount it again. I have a Windows computer as well so I accessed the NAS from windows and deleted all files in the directory .AppleDB in the root of the share that crasched. When this is done I can connect again but the problem re-appears as soon as I copy a large file again.
I have tried both over LAN and Wifi but there is no difference apart from the speed.
Last but not least, the Time Machine don´t work either. I can see the disk in Time Machine but when I select it for backup the process starts, Time Machine says something like "Connecting to disk" in about a minute, then it stops and reports an error.
I am so far very dissappointed with the device but hope someone can help to solve these issues. I hope there is simple solution to the problems or at least a new firmware on the way!
Anyone who can help with these problems?