Your program looks like an unfinished thought :) you never setup the xml parser ...

JMeter docs hint it comes with a mailer and xsl for fomatting report http://svn.apache.org/viewvc/jmeter/trunk/extras/jmeter-results-report.xsl?view=markup, but if you insist on perl, use XML::Twig; # its pure-perl built on top of XML::Parser

Write it like this, use autodie for automagic error checking

#!/usr/bin/perl --
use strict; use warnings;
use autodie;
use XML::Twig;

Main( @ARGV );
exit( 0 );

sub Main {
    parseJmeter( \*DATA, \*STDOUT ); # DEMO
}

sub parseJmeter {
    my( $inFilenameOrHandle, $outHandle ) = @_;
    my( $error, $value, $failure, $failureMessage ) = ("") x 4; # INIT
+ TO EMPTY

    my $t = XML::Twig->new(
      twig_handlers => {
        'failure' => sub {
            warn $_->path;
            $failure = $_->text;
        },
        'failureMessage' => sub {
            warn $_->path;
            $failureMessage = $_->text;
        },
        'error' => sub {
            warn $_->path;
            $error = $_->text;
        },
        '/*/*//httpSample' => sub {
            warn $_->path; ## children
            $value .= $_->att('lb') . "\n";
        },
        '/*/httpSample' => sub { # TRIGGERED LAST, the daddy httpSampl
+e
            warn 'YO ', $_->path;
            $value .= $_->att('lb') . "\n"; ## append
            print $outHandle  qq{
<tr><td><p>
$value
</p>
<td><p>
$failure
</p></td>
<td><p>
$failureMessage
</p></td></tr>
};
            ( $error, $value, $failure, $failureMessage ) = ("") x 4; 
+ # RESET TO EMPTY
        },
      },
    );

    $t->xparse( $inFilenameOrHandle );
    $t->purge;
    return;
}

__END__
<?xml version="1.0" encoding="UTF-8"?>
<testResults version="1.2">
-- HTTP Sample, with nested samples 
<httpSample t="1392" lt="351" ts="1144371014619" s="true" 
     lb="HTTP Request" rc="200" rm="OK" 
     tn="Listen 1-1" dt="text" de="iso-8859-1" by="12407">
  <httpSample t="170" lt="170" ts="1144371015471" s="true" 
        lb="http://www.apache.org/style/style.css" rc="200" rm="OK" 
        tn="Listen 1-1" dt="text" de="ISO-8859-1" by="1002">
    <responseHeader class="java.lang.String"></responseHeader>
    <requestHeader class="java.lang.String">MyHeader: MyValue</request
+Header>
    <responseData class="java.lang.String"></responseData>
  </httpSample>
  <httpSample t="200" lt="180" ts="1144371015641" s="true" 
     lb="http://www.apache.org/images/asf_logo_wide.gif" 
     rc="200" rm="OK" tn="Listen 1-1" dt="bin" de="ISO-8859-1" by="586
+6">
    <responseHeader class="java.lang.String"></responseHeader>
  </httpSample>
  <responseHeader class="java.lang.String"></responseHeader>
  <requestHeader class="java.lang.String">MyHeader: MyValue</requestHe
+ader>
  <responseData class="java.lang.String"></responseData>
  <cookies class="java.lang.String"></cookies>
  <method class="java.lang.String">GET</method>
  <queryString class="java.lang.String"></queryString>
  <url>http://www.apache.org/</url>
</httpSample>
</testResults>
[download]

Since http://search.cpan.org/perldoc/XML::Twig#text doesn't return encoded data, you should look into using http://search.cpan.org/perldoc/XML::Twig#html_encode

I also recommend perlintro, http://learn.perl.org/books/beginning-perl/, http://perl-tutorial.org/, Modern Perl