Here's the error message I get when I login at /wp-login.php or when I try to access /wp-admin :
Fatal error: require_once(): Failed opening required './admin.php' (include_path='.:/usr/lib/php6') in /homepages/7/d90932975/htdocs/ChristianWomenSpeakersMovement/wp-admin/index.php on line 12
I've re-installed the latest version of WordPress (3.5.2) but only the wp-admin and wp-includes files (via ftp). This version was already installed and it was working fine until a few days ago. No new plugins were added in at least a couple of weeks. No changes were made to the theme either. I did rename the plugins folder and theme but it didn't help.
Of note, there is a member area that I can log into but still can't reach the admin panel.
Any help would be greatly appreciated.