403.14 error after installation

I am new to WordPress so maybe there is a simple fix that i am not seeing.
The installation went fine – i got the confirmation email and all that, but I cannot access the /wp-admin page.
I installed the app to /blog. When I log-in (www.example.com/blog/wp-admin/) I get this message:

HTTP Error 403.14 – Forbidden
The Web server is configured to not list the contents of this directory.
I can access the login page by using http://www.example.com/blog/wp-login.php
but after entering the credentials i get the 403.14 again.

Some other post suggested that the index.php is not allowed ??
Any ideas?

Thank you