Settings Page in WordPress Admin will not load

On a website I maintain my “Settings” page will not load.

http://www.mydomain.com/wp-admin/options-general.php

This page (http://www.mydomain.com/wp-admin/options-general.php) loads fine as does (http://www.mydomain.com/wp-admin/options-reading.php) and a few others.

Some plugin specific pages also refuse to load.

http://www.mydomain.com/wp-admin/options-general.php?page=featured-content-gallery/options.php