Read more tag not working

The read more tag <!–more–> is not working in my posts. I wonder if the problem could have anything to do with this: I’ve actually inserted sub-pages, organized by category, into my main posting page. I’ve done it with a plugin that allows me to do so like this: [posts-to-page cat_id=8]

That’s an example. The code above corresponds to my page that contains all my posts under the category Islam and Islamic Cultures. Then I’ve got other categories, organized as other pages. For instance: I’ve got a page that’s dedicated to posts on Language and Linguistics. So that’s the background.

[ Link fixed ]

http://www.brainybooks.org/

Could this possibly be what’s screwing up the <!--more--> code? Any other ideas?