If you are still having a problem:
Have you tried joining through the online lobby? What about Direct Connection after exiting out of Galaxy and starting the game directly from the executable?
You could try LAN, but since you are not on the same local network, it would require using VPN software (such as Hamachi or Tunngle).
Are you shutting down all non-essential programs (especially anti-virus) before starting the game?
It sounds like the issue is on your end, given the error changing settings, but have either of you tried playing with anyone else?