Admin accounts messed up after merger

[peepo]

Hello, Since I merged punbb into mybb the admin accounts are messed up.
I cant access admin permissions via the admin control panel because it sais my admin account doesnt have access. But when I found the Super Adminaccount & logged in with it, it wouldnt let me into the admin panel.
I think its because I gave this new admin account the same name as one of the admins from my old forum, so now the account is in limbo.
Does anyone know how I can rectify this?
Thanks