I doubt that SDL_mixer is source of problems here (and if it’s not working, it should do nothing or crash VCMI but not mysteriously sabotage loopback connection).
If SDL / boost work well enough to allow scenario selection and connecting via telnet to the server, they should also allow playing game.
Error message is pretty clear:
Problem with resolving:
system:-2147483643
Server is running in background and it’s connection is working (as you confirmed by using telnet), the problem lies somewhere in the networking code of client.
Take a look at lib/Connection.cpp, line 70 and further. That’s where connection to the server is established.
tcp::resolver::iterator end, pom, endpoint_iterator = resolver.resolve(tcp::resolver::query(host,port),error);
That line for some reason fails.
If there is server application listening on port 3030 of localhost, I see two possibilities
a) host and port arguments are invalid (I don’t see any rational reason for that but who knows). try logging them before the feral line:
tlog0 << "Host: " << host << " Port: " << port << std::endl;
They should be “127.0.0.1” and “3030”.
b) boost::asio resolver doesn’t work properly with HaikuOS.
(You can try to reproduce the issue on the examples from asio documentation boost.org/doc/libs/1_42_0/do … mples.html )
You may also try to figure out what that error code means (-2147483643). Maybe Haiku has somewhere documented error codes. Maybe strerror will give something.
Thanks for the interest in our project and good luck! 
