I am running Drupal 7.56, with PHP 5.6.31.
I upgraded to CiviCRM 4.7.29, and now my membership renewal page .../civicrm/contribute/transact?id=1 comes up with HTTP ERROR 500.
The PHP error log shows this: PHP Fatal error: require_once(): Failed opening required 'CRM/Core/.php'
It is trying to load a ".php" with no name before the extension. What could cause that?