Login problem using NT Authentication

First off, my apologies if this has been answered previously, I used the search but didn't see anything related to the problem.

I'm using NT Authentication on our forums.  The problem is, when the user first visits the page, they seem to be logged in as a guest first, then if they refresh the page they get the logged in user's options.

For example, we have 'no access' to all forums for guests, so anyone visiting the forums sees the no access icon unless they refresh the page first.  Admin and Moderators won't get the top menu bar options until they refresh either.

Any ideas on how I could fix this problem?

Thanks!