Can't play with 2 people on the same network

[thestix 0]

So I bought dayz my gf watched me play it and she wanted to play too. I ordered a new graphics card for my old pc, and set it up for her to use, but we cant join the same server. It always gives the person joining the "you have been kicked" message. I ordered a new router hoping that will fix the problem(plus I really need a new router anyway mine is ancient), but I'm wondering if anyone knows any other solutions to this problem.