Trying to get property of non-object in concrete\models\config.php on line 60
But here's how you can fix it in the meantime. Go into "index.php" and above the line that includes dispatcher.php (the only line), add:
error\_reporting(E\_ALL ^ E\_NOTICE);
Right now your system is setup to display notice errors, which C5 usually turns off but unfortunately there's a notice error (nothing serious) that occurs before we do that, which is why you're seeing it on every page.