I now see what appears to be the problem. I was trying to insert an image into a Text Block in the Advanced Layout Editor. The “Insert into page” button works fine if I’m inserting it into the Image media element. Sorry guys. False alarm.
I’ve also re-installed WordPress 3.6 & enfold via FTP, but I still had the same problem — could only add Media to posts and not pages.
If I change the theme to twentythirteen I *can* add media to pages once again.
When adding Media to a page or post, the “Insert into Page” button does not work (though it *does* work when inserting media into a post).
Screenshot: http://focusonhealthbc.com/support/insert-into-page.png
Yes, I did try disabling all plugins, but that didn’t help