I know this is a very old post, but in case anyone arrives here via Google, I wanted to note that this tutorial is misguided. There's absolutely no reason whatsoever to use XML::Parser, and the code above is needlessly complex. There's also about three times as much code as you need for something this simple. So why not use XML::Simple? It's pretty straightforward:

use warnings;
use strict;

use XML::Simple;

# Just an example. You'd use LWP to get the actual CB.
my $xml = '<CHATTER><INFO site="http://perlmonks.org" sitename="Perl M
+onks">Rendered by the Chatterbox XML Ticker</INFO>
    <message author="OeufMayo" time="20010228112952">test</message>
    <message author="deprecated" time="20010228113142">pong</message>
    <message author="OeufMayo" time="20010228113153">/me test again; :
+)</message>
    <message author="OeufMayo" time="20010228113255">&lt;a href="#"&gt
+;please note the use of HTML tags&lt;/a&gt;</message></CHATTER>';

my $ref = XMLin($xml);

foreach my $msg (@{$ref->{'message'}}) {
  my $h = substr($msg->{'time'}, 8, 2);
  my $n = substr($msg->{'time'}, 10, 2);

  my $author = $msg->{'content'} =~ s/^\/me// ? $msg->{'author'} : "<$
+msg->{'author'}>";
  print "$h:$n $author: $msg->{'content'}\n";
}
[download]

Now you have a complete a simple parser. And no dodgy regexes, either.