Really weird admin navigation problem

I just installed WP 2.0.3 (have used all previous versions before, on this and other webhosts). This is the most obscure bug / error I have ever seen in wordpress. To be honest, the first.

When I click “Write page”, it goes to “/wp-admin/page-new.php”. But it renders “Add new link”-page instead. Same bug is if I press “Add link”, it goes to “/wp-admin/link-add.php” but renders “Write Page”. Same problem appears aswell on lots of other links within the admin navigation, so it isn’t just those two.

How is this even possible? It’s a fresh install. No plugins or other modifications what so ever has been made. What can be wrong here?