this has been discussed here;
Ch 2 Page 53: Undefined index: authuser
however I think there are problems that haven't been solved as of yet.
First: there's no discussion of how to set up php.ini even though it says so in the book.
(Also, make sure before using sessions that your php.ini file has been modified to show a valid path for
session.save_path , as described in Chapter 1 .)
page 38, yet there's no mention of that in chapter one.
Also I have no idea how to solve the problem ...