I'm new to this and will appreciate for any help/ guide anyone can give.
An hour ago, I've just registered with BB App World and paid $200. Right after that, I can't sign in to Vendor Portal for BlackBerry App World™ almost instantly. However, I can still login to the other website na.blackberry.com/eng/developers
Is that normal? What will happen next and what should I do?
It can take 24 hours for your App World registration to take effect. it usually happens way faster than that, but waiting several hours is common. You might want to check with whatever method you used for payment and confirm that the purchase went through.