Update: With the permalink settings in default mode, I made a new "security" page that is working. The page won't work if permalinks are in any other setting besides default.
I see what you are saying about Pages vs. Posts. This is a Page that I added to the website. I now see that permalink settings are supposed to apply to Posts. So why do the permalink settings break my Page?
Still looking for a solution that will make my page URL pretty...
Current page URL: http://rmgfund.com/?page_id=169
Desired page URL: http://rmgfund.com/security
[password moderated]