In Moodle, why is a particular page blank or incomplete?

It might indicate that an error has occured when Moodle is trying to display a page. Please let you system administrator know about the problem.

(Details for system admins: Depending on the server’s configuration, PHP might hide error messages. If this is the case, when an error in a PHP script occurs, PHP might choose to not display anything, resulting in a blank page.

Usually, PHP should not display error messages in a web page for security reasons. However, there are exceptions, e.g. when you are debugging a web page.

To globally enable error messag display, put these in your php.ini file:
display_errors = On
error_reporting = E_ERROR

To enable that for a single PHP script, put these at the beginning of the script:
ini_set(‘display_errors’, 1);
error_reporting(E_ERROR);

See the Moodle FAQ for details.)