CGI::Carp is a different module. From the error you are getting, I am assuming you replaced use CGI with use CGI::Carp qw(fatalsToBrowser);. Wrong! You need to start off with what I have below. I've included diagnostics to explain any errors in further detail. On top of this, you say you are checking for errors with open() and close()... I don't see that in your code.

#!/usr/bin/perl -w

use strict;
use warnings;
use diagnostics;

use CGI;
use CGI::Carp qw(fatalsToBrowser);

# rest of script here
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