This is a problem that I have never been able to solve on my DNS-323. It has firmware version 1.09 and one 2TB WD20EADS drive installed.
Here is the problem:
Navigate to Advanced>UPnP AV SERVER -or- iTunes SERVER.
Enable either server
Uncheck root
Type anything into text box next to "Browse" button. Nothing happens.
Click Browse button and try to select folder. It will never let me select a folder, only drill down through them. Even the topmost folder. At this point, if I try to type the folder path in the available textbox, the text shows up briefly and then goes away so no folder can ever be selected.
The same thing happens when attempting to set up users and groups in Network Access Settings. Folders are unselectable and the folder textbox doesn't fill with any path that I type.
Tried this on both Win7 and Vista machines and in a variety of browsers and have reset the device many times but to no avail. Am I missing something here?