It is correct yes, because otherwise it wouldn't run correctly locally.

Not true. When run as CGI, it has other obligations to meet. I said that already.

if server had those 2 files 500 and 404 the site would still had trouble run, correct?

Yes, it won't help you at all. That's why I said you could ignore them.

Just tried this script now:

#!/usr/bin/perl -w
use strict;
use CGI::Carp qw/fatalsToBrowser/;
use CGI qw/:standard/;




#======OK, $data set up. Now print header, start_html and JavaScript s
+tuff======

print header();
print start_html();

print "hello niko";
[download]

still same erroe message. what could possibly be the problem? this is getting on my nerves.

Except possibly for the path to Perl, that's fine if run as a CGI script.