Dear peoples,
yesterday I bought the new Theatrhythm Curtain Call. I tried to go online in VS mode but I got the error 018-0512.
On the Nintendo support site it told me to change my IP address on the 3ds and enter it in my router in DMZ.
I did that, hopefully correct...
Sometimes, it works. I played for half an hour with the same person, but after that, when I tried to connect again to someone else, it got blocked again. No matter what I tried after that.
Perhaps someone could help me with the DMZ. I guess I did something wrong.
Or is there a way for my firewall not to block my 3ds? To just grant it access to whatever it wants 
Some extra info:
My internet works fine on the 3ds. Just connecting to others doesn't work.
I've got a linksys router.
My IP address seems different when I look it up under whatmyip.com, perhaps that's an issue?
I'm gonna call customer support this monday when they're open again.