I had several Pyrocms installs going failed on me when I tried to login with Firefox or Chrome. With Safari I could login just fine.
It looks just like you are being logged in but the login screen stays on focus and no error is returned.
It appears that there is some issue with the cookie domain if you are installing it on an test environment like XAMPP or LAMP.
After editing the following file and changing the cookie domain I could login just fine.
$config['cookie_domain'] = (isset($_SERVER['SERVER_NAME']) AND $_SERVER['SERVER_NAME'] == 'localhost') ? '' : preg_replace('/^www\./', '', $_SERVER['SERVER_NAME']);
changed to:
$config['cookie_domain'] = (isset($_SERVER['SERVER_NAME']) AND $_SERVER['SERVER_NAME'] != 'localhost') ? '' : preg_replace('/^www\./', '', $_SERVER['SERVER_NAME']);
(the == had been replaced by != )
