#! /usr/bin/perl
use strict;
use warnings;
use URI::Find::Schemeless;
use HTML::Entities qw(encode_entities); # changed

my $text = q~
   hello this is no.url
   this is an url: www.fabiani.net
   ftp.anything.de/test/thisfile mailto:martin@fabiani.net or the like
   yeah martin@fabiani.net http://www.fabiani.net/
~;


# create a new URI::Find::Schemeless objekt and add as callback 
# the function what shell be done with each found URI
my $finder = URI::Find::Schemeless->new
  ( 
    sub {
      my ($uri, $originalUri) = @_;

# error: encode_entities is missing
#      return qq~<a href="$uri" target="_newpage">$originalUri</a>~;

      return 
        q/<a href="/ . encode_entities("$uri") . q/">/ .
        encode_entities($originalUri) . q/>/;

    }
  );

# here starts the search (and in our case the replacement):
my $howManyFound = $finder->find(\$text);

# lets have a look at the result
print "$howManyFound URIs found\n";
print "$text\n";