Have you tried without the mods? Can't speak for this game but other games I've played with mods sometimes had issues like this due to mods. You don't have to play with it like that, just for long enough to prove whether the mods are the culprit. Beyond that, how are you connecting to the game (wifi...

To be honest forwarding ports on a router is trivial compared to trying to setup OpenVPN or whatever else you're trying. That said have you enabled UDP in uTorrent? Not sure if this setting is default on but under the BitTorrent section under settings there should be an option to enable UDP tracker ...