This may be too late for you now but I have only just bought a unit but it may be of use if anyone else experiences the same problem.
I had the issue when I set mine up (firmware v04.01.02-417) ie. “no media files in DLNA server list (the media database,on the other hand is OK)” so the dashboard knew the content was there.
I managed to resolve it by accessing the twonky server using a browser (address http://ipaddress:9000 not mycloud:9000 as this didn’t work for me) and going to the “sharing” section. The share was shown as “/Public” so I hit the browse button and remapped the share and it showed up as “/shares/Public”, other folder I manually typed “/shares” in front
Once this was done it went off and found the content that I had on the drive and listed it in the DLNA Media Server section, I also did do a rescan just to be sure.
Hope this helps someone before they get as frustrated as I’ve been !!