If WP QUADS detects that the_content filter is missing on posts and pages you need to fix this first before WP QUAD is able to inject ads into your website.
This filter is used by WordPress and by many other plugins to modify the post content before output. Even though this filter is essential some WordPress developers tend to forget this or use the get_the_content() and not the_content() to output any content.
If you can not fix this on your own ask your theme developer to solve this.
My personal advice:
Switch the theme!
If such essential function is missing in a WordPress theme it’s highly likely that this theme will lead to other serious issues and makes you more trouble with other plugins
Known plugins which are not using the_content filter:
– bbpress forum plugin
