On the Arcade main screen it says Welcome Guest with the option to login or register. if I try to login (I've already registered a while ago and have a Jet Pack example on the Arcade) it takes me to http://www.scirra.com on which I'm already logged in. If I then click on the Arcade menu it takes my back to square 1, on the Arcade main page asking me to login or register.
Even if I click upload a game it still takes me to http://www.scirra.com.
I can't even comment on games as I'm 'not logged in'.
I'm using FireFox v29.0.1