Hi badduck,
i was having the same problem.
I had a Network Location to my DNS-320l and suddenly I cold not access my DNS by the Network Location. I could still access my DNS by web browser and FTP.
Then I checked Network Share and there was nothing there. I tryed to create a new Network Share but it didn`t appear in the grid.
After trying many things, I decided to format the HDD, but the DNS would not format the HDD.
I had Fun Plug and Debian Squeeze intalled, so I decided to delete those files manualy by accessing the DNS by web browser.
I deleted first the fun plug files and restarted the DNS. After that I checked the Network Shares and Volume_1 was at the grid. So i tryed again to create a Network Location and I was able to do that.
So, if you have Fun Plug intalled on the DNS try removing it!