#!/usr/bin/perl

BEGIN {
   eval ("
      use LWP::UserAgent;
      use HTTP::Request::Common;
   ");

   if ($@) {
      print "500 Internal Server Error\n";
      print "Content-type: text/plain\n";
      print "\n";
      print $@

      die($@);  # For the log file.
   }
}

print "Content-type: text/html\n\n";

my $ua = LWP::UserAgent->new;
my %post = (...);
my $response = $ua->request(POST "http://www.example.com/", [ %post ]);
print $response->as_string;