hey there, i had the same problem a few days ago, it said i wasn't allowed to make a forum account at this time. I came back today and tried and it seems to be working, maybe you should ask your friend to try again, hopefully he's in luck like i was ;)
I believe the forums, like the PTS, only update their log-in/password files once a day (at 6:00am CST.) You can sign-up and play the game immediately, but you have to wait until the next day to get to the PTS and the Forum (to post.)