I've met one problem when Register User or Guest can't see CMS content, appear:
Quote: Manaa, you do not have permission to access this page. This could be due to one of several reasons:
Active your account by follow the link that you will receive an email in your inbox.
Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system?
If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation.
I edited "Usergroup manager" for groups can view in control panel at.