Programming :: Unable To Access Filehandles (Perl)

I've been reading / trying to learn some Perl lately. I've found the free book, "Learning Perl", quite good and easy to follow most of the times. However, today I was testing one of the scripts in the book and it would only run partly.

Code:

#!/usr/bin/perl
use warnings;
use strict;
my %inventory;

[code]....

This row is supposed to give option, either to use an additional script as pipe (sort.plx),or STDOUT if the extra script is not found.It works with the other script present, however, with the sort.plx being absent it simply wont use STDOUT instead but whines to me:

Can't open perl script "sort.plx": No such file or directory

Has the author of the original script done some error writing it? Since I'm a beginner and found most of the stuff confusing in Perl either way (having previously only experience in Bash and some in PHP) - I can't really tell for sure , but from what I can read in documentation - it doesn't appear to be wrong.As it looks now, the only way for me to use STDOUT is only by removing:

open (SORT, "| perl sort.plx") or *SORT = *STDOUT;
select *SORT;

rows. But then, I lose the piping in to that other script as an option.