That sounds ok since the object_id from site_nodes is a site_node (basically the front page of your OpenACS instance), and shouldn't show up in cc_users. :) In your 'select acs_permission__grant_permission call, you're saying "give the public (-1) permission to read the top site node (2505).
Actually, I don't think this is what you needed to do. What you've done would be appropriate if you couldn't get the login page to even come up. Is that what's going on? I pointed you to that FAQ because I thought you needed to make a new site-wide administrator, since your current account doesn't seem to be able to access acs-admin. If I'm understanding your problem correctly, you need to follow the directions in the second part of the faq that talk about creating a new user and making them the site-wide admin.
Please post again if still stuck :)