i cannot display Dashboard > Sitewide Settings > Debug. it renders a blank page.

i am using 1 concrete directory for several dev sites. i have modified several files to account for this:
- apache config file includes alias for concrete directory
- path to concrete directory is accessible from php. i access the directory by calling:
require('concrete5/5.4.0.5/dispatcher.php');
- index.php includes require for dispatcher.php (see previous line)
- site.php defines DIR_BASE_CORE and is assigned the absolute system path to the concrete directory

all works with exception of said page.