First off, you are I assume using the gui to minidlna, called DLNA Server.

Anyhow, lets look at minidlna. Go to terminal and try

and see if it spits out any error.

You should perhaps run this under "sudo" as minidlna appears to run as root rather than user.

And I would reboot after the installation if you have not done so already. Mine works just fine (both server and gui) so there is not a clear problem with either programs.

There is another server (and player combo) called dlnasender. Perhaps try it too.