Re: User authentication
Hi!
As a admin user, Expand the Admin menu and click Groups
Click the Registered group and add permissions for the various "Features" you have enabled. Such as allowing view to forum posts, etc.
You may want to also modify such permissions for Anonymous.
You might also find the Tiki Flash movies useful: http://tikiwiki.org/TikiMovies particlarly the Preliminary_Settings
Post back if you still have trouble!
Damian