Hi,
I actually cannot help you directly with that but we have merely the same problem - similar configuration, instead of a Cisco Router we have an Astaro Router/Firewall. Obviously, the named ports (TCP and UDP) are NOT sufficient for the communication. When we observe the traffic between screen and server (using the well-known and excellent freeware "Wireshark", just google for it -simple to set up and use), there are numerous more IP packets with varying numbers that are exchanged between server and screen. I tried to evaluate this in more detail but was not successful so far - I am not a network guy ..
If we configure the router as completely transparent between the two subnets (which I do not recommend due to security issues) and also shut down the windows firewall on the server PC, everything works fine. Screen and Server can find themselves.
If we start MagicInfo Pro, let it find the screen, and then start the windows firewall (of course, with the ports you named as being open), still everything is fine. The server finds the screen, all (including uploads to the screen) works perfectly.
If we start the Windows firewall BEFORE we start MagicInfoPro, we have the same effect that you have - the server does not find the screen. And again, in the windows firewall, the named ports are all still OPEN.
This means that MagicInfoPro on the server PC uses some additional TCP/UDP ports for finding the screens during the startup of the software. As soon as it has found the screen, those additional ports are no longer used or necessary.
Those ports are not the multicast protocol packets (MCPs) which you will find in a Wireshark analysis, since they usually do not go across routers (only few routers support multicast routing, mostly when Apple protocols (Bonjour) come into play).
You now need to find out the right TCP and UDP ports - I still hope that Samsung can tell us which they are -. add them to your Cisco router configuration, and everything will be fine.
Maybe you can identify them with Wireshark - would be great if you can post them when you are successful.
Sincerely
Gerald