in pma 2.11 a bad configured session.save_path triggers an error page:
"Cannot start session without errors, please check errors given in your PHP and/or webserver log file and configure your PHP installation properly."
No such hint in pma 3.x any more, the login just reloads.
simple test (for .htaccess):
php_value session.save_path "/thisDoesntExist"
same in scripts/setup.php :
pma 2.11 -> "Cannot start session ..."
pma 3.x -> "seems" to work but obviously can not (only creates an empty config file) .
Fixed in subversion, thanks for reporting.