That is the error I get all of the time and WP Engine said it can't be cleared, so there isn't an actual PHP error in the terms of WSOD (white screen of death). That error doesn't cause WSOD.
Warning: include() [function.include]: Failed opening '/nas/wp/www/staging/~~~~~/wp-content/advanced-cache.php' for inclusion (include_path='.:/usr/share/php:/usr/share/pear') in /nas/wp/www/staging/~~~~~/wp-settings.php on line 58
Without knowing your setup, I'd guess that you have another plugin conflicting with it. Is that blank page /wp-admin/ or /wp-login.php?
Drag all other plugins into another folder (don't visit the plugins page in the dashboard in any old tab) and refresh the WSOD page. If it's still blank, it's not a plugin and then drag them back in. Let me know your findings.