I have and Intel I5 with 4Gb RAM on Win 7 64-bit.
I trialed the free version of Mezzmo and it worked great.
I have now paid for and registered the full version 2.5.0.0.
I am connecting in exactly the same manner using cat-6 Ethernet cable thru my 24 port Gigabit switch.
I choose media server on my Panasonic Viera TH-L42U30A and in the list, I can see Mezzmo.
The Mezzmo name is there but the icon is just a black box.
With the free version the icon was the two green arrows.
When I choose Mezzmo, it says "reading" for around 10 seconds and then comes up with the message "connection to the server failed".
I have uninstalled and reinstalled the software without success.
My Media Server is running and I can see my Panasonic in the Device List.
All IP addresses are correct.
My TV can still use Windows Media Player to access files on the same computer.
What have I done differently, apart from pay for the full version???