Joining multiplayer

I have two boxes here. I would like to test out multiplayer on them. So first I start a game on one, but I click the little checkbox for hosting game as server.

Then as I understand, I should go to the other box and query to see what games are on the lan. Once this is done, I select to launch that game which shows up right? Problem is every time I do this, after it is completed loading all objects, the game crashes on the box trying to enter. Curious to what could be the problem here, thanks.