What should I do if I can access http://127.0.0.1 but not the MiniPortal EP Setup page (http://127.0.0.1/admin/setup/index.html)?
This is most likely a timing problem between your web server startup and your browser startup. The browser may try to access the Setup page before the web server has finished initializing. Try to flush your browser cache. In IE, select Tools->Internet Options->Delete Files and check ‘Delete all offline content’. Exit IE and then restart it. Rebooting the machine may help, or just letting a few minutes pass before you try accessing the Setup page again may work.