Tip. Keep it simple. Try this first:

#! /usr/bin/perl -w

use strict;
use CGI;

my $query = new CGI;

print $query->header();
print $query->start_html( -title=> "CGI");

while (my $size = read($cgi->param('file'),my $data,1024))
{
  print $data;
}
print $query->end_html;
[download]

STDOUT is the default filehandle, so no need to specify it.