Any help appreciated- Here's what's happening. User

Any help appreciated- Here's what's happening.

User is a subscriber. After logging in he is redirected to a welcome page. This welcome page has some links that go to the Dashboard. The Dashboard is accessible by clicking in on its links in the admin bar on top. Any link in the welcome page that points to a URL in the dashboard doesn't work. These links do not have the www in its URL, the link format only has the domain as in http://domain.com/wp-admin/index.html - when I say that it doesn't work, I mean it resolves to the domain but it logs me out and redirects to the log in page wp-login.php

Any idea why?, is it htaccess, wp-config, or a plugin?

Thanks,
Joe