I think that's going to be a problem with the user Activation and having restricted access to your Forums.

Nuke will override your Forums.

You have the Forum set to registered users only. So if a user signs up, the redirect at the end of sign up takes them to the Forum index, BUT they caqn't get to the Forum index because they have not yet been activated and are not yet fully registered.

Need to figure out where that redirect at the end of registereing is generated. Maybe if you can find that and change it to take them to the Home main Nuke page...?

mikem