While logged in with the account i'm using with SC2 Beta, i get the following message here in the forums:

"The account you are logged in with is not able to post on this forum. Please log out and select a different account if you want to post."

I have no way to report/confirm/discuss any issues i might be having with the game. Why might that be?

I must invited by a friend during the first "invite" wave.

Thanks.

Are you sure that you are trying to post on the EU forums? Seeing you are playing on Europe, you might have just tried the US forums.

This would be the correct ones if you have EU StarCraft II access:
http://forums.battle.net/index.html?sid=5010

Also, you will have to have logged into StarCraft II and created a profile before you are able to post.