Long time ago (well a few years), I wonder if there wasn't someone else who had problem with disconnects after say each 3 minutes.
If I recall right, he also ran bittorrent software on his computer. (It doesn't have to be on same computer; it could be on any computer in the "inside" of the network/"router".)
How Bittorrent could interfere with entropia: Let's say you start to download 10 files. Each of the files are availible from, say, 2 people. And, each of *your* files (ie started downloads) will be shared to 2 people. This means you will have, uh, 10*2*2 (40) Connections. Add more files, and more sources and destinations and it will add up.
The problem here is, a modern "router"/firewall will have a Connection table. When you connect to a host on the internet, the "router" will make a note of which of the IP addresses on the inside has connected to which IP address on the outside, and which port on the inside is connected to which port on the remote computer. This Connection list is needed to be able to have several computers on the inside sharing same IP address on the outside and be able to connect at the same time - consider both computer A and computer B, at the same time, is connected to the windowsupdate server at same remote port (80); the list makes sure that the right computer on the inside gets the response that *that* computer is expecting and not Everything that the remote web server sends. (This list can also be used to make sure that computers on the internet, that has no Connection according to the list, can't send data to the computers on the inside simply by trying to send data to the temporarily opened ports and make sure that a remote computer doesn't try to send data beforeo the TCP Connection is properly opened aka "stateful inspection").
The problem here is that that the size of that list, that is kept in RAM of the "router", can be limited to, say, 1024 entries. 1024 entries is usually more than enough (eg 512 opened web pages from the inside at same time); but if someone on the inside is using a Connection-hungry program, this list can be depleted. And, with bad luck, if it happens the "router" can flush the entries that are used for Entropia, effectively blocking entropia traffic (as the "router" no longer knows which internal computer should receive data sent from entropia game server). Meanwhile, the torrent program seems to work normally. The torrent program will probably suffer also, but as it might have hundreds of Connections opened anyway, and that it can start up new Connections by itself, it's not noticable (for the bit torrent client it will just look as if one of the remote Machines just rebooted or something.)
So to sum it up, try to figure out if you have any Connection hungry software, like Bittorrent (could also be TOR node software or, well anything that opens up Connections by itself). Or if your computer either is under attack from some "hacker" (someone tries to open all ports to see whats' vulnerable in your network), or if your computer itself is infected by a worm trying to spread to random remote hosts.
If I remember right about the ports, the ones you needed to open "inbound" was because of some ancient streaming audio protocol, and the FTP ports are used to upload/save Beauty masks you've designed. Possibly also to upload customized ad-screens (ad screens with photos etc). You probably won't get disconnected by missing opening up those ports, but rather not get streaming audio and not being able to upload "customized content".
(Port 554 = "Real-time Streaming Protocol (RTSP)", port 30583 probably game setup, port 30584 probably game data; gamer friendly "router" probably automatically puts this in the Connection table - but here probably the problem lies if Connection table becomes full).