There are situations where the root cause for an error is not clear and requires extra steps to detect.
By default Pagekit will hide any PHP error, in order to show it the Debug Mode must be enabled in System > Settings or set to true in the configuration file manually.
Note If the error happens during installation the configuration file will not exist. In such case you should edit the default config file located in app/installer/config.php.
The same way you may enable the Debug Toolbar which will provide some useful information about the environment. Notice that some server errors may prevent the toolbar from being displayed.
Remember to disable the Debug and Debug Toolbar when the site is deployed on a production server.