Hello!
In other posts I read one mistake in the file main.php

// 401 file referenced since user should be logged in to view this page
//include '401.php';

the sentence include '401.php'; appear as a comment. So I deleted the two diagonals. But when I uploaded to my server, appear's nothing in this page(main.php) like some type of error. Then, I deleted the sentence include'401.php', and it works with out problem, but I can see this page without login, It`s because whe call 401.php, but does not work with this sentence.
someone knows why?
thank you

Hi acevedoalej,

You include a 401.php file at the top of a page
to protect that page, so only people who are logged in can
see it. Basically the 401.php script checks to see if the user
is authenticated and if not it redirects them back to
the login page. The book has a good discussion of this on
page 24, the last five lines.

As far as the actual content of the 401.php file goes,
I am using the code out of the book (not the download code)
and that is working for me.

I hope this helps.