Hi, I am not getting what is happening at your site. I have tried so many things at my localhost but nothing prevents like this. Might be some some, you can try with debugging on at your site, set it to developer and display debug message to yes.
This was the solution to my problem.
In order to display certain blocks on your front page you must do the following:
Login as admin. Go to Site Adminsitration -> Users -> Permissions -> User Policies.
Then enable Auto-login guests option.