Forum landing page

I want to establish one of my forums as application (and landing page for my intranet): http://discussions.zoho.com/intranet/forumX
When I'm logged in as administrator, everything is all right. The button in the left navigation bar leads me to the correct forum.
But logged in as one of the users, I see http://discussions.zoho.com/intranet/ (the 'all forums' page) instead of http://discussions.zoho.com/intranet/forumX. How can I change that?

Arno.