To post in every part of DAI forum, you need DAI associated with your profile.
Close.
To post in the restricted Dragon Age forums, you will need a registered copy of DA:O, DA 2 or DA:I on your profile (this is handled through the EA account system.) Any of the three games will provide access to all DA fora, so you don't necessarily need DA:I for the DA:I forum, any of the three games will do.
To post in the restricted Mass Effect fora, you have to have a copy of ME, ME 2 or ME 3 registered (again, any one will activate posting privileges for all ME fora.)
My account here is different than the one i have on the game because i forgot the password and when i tried to recover it by making EA resend the password recovery to my email i use for the account, the email didn't appear at all. So i had no choice but to create new one.
You won't be able to post in the story/campaign forum until a registered DA game is on the profile. You might be able to resolve this yourself or with EA support, but I suspect that you may need a BioWare employee to merge the accounts.
You may need to wait until one has a chance to look into that for you.