#!/usr/bin/perl

# use module
use strict;
use warnings;

use XML::Simple;
use Data::Dumper;


# create object
my $xml = new XML::Simple (KeyAttr=>[], ForceArray => ['function']);
#                                            IMPORTANT ^^^^^^^^^^

# read XML file
my $data = $xml->XMLin("hosts.xml");

my $e = $data->{'host'};
print "Name: ", $e->{name}, "\n";

# IMPORTANT: Use a loop to process all the possible
# functions, instead of just one.
foreach my $fct ( @{$e->{'function'}} ){
    print "Function: ", $fct, "\n";
}
[download]

<allHosts>
   <host name="jimmy">
      <function>web</function>
      <function>dns</function>
      <location>miami</location>
   </host>
</allHosts>
[download]

Using your code, I get the following error

Pseudo-hashes are deprecated at ./test.pl line 19.

Please don't just "use my code". Your XML file is different from the block I used, in that I only have one host and you have several.
The key point (I'm sorry if it wasn't clear) I was making was that XML::Simple returns a reference to an array when there is more than one element with the same name. You need to either differentiate between the "singular" and the "plural" using ref, or force the element to be an array reference all the time using ForceArray => 1 in your options.
The structure and form of the data XML::Simple returns depends on the XML it parses. I think that's the crux of your problem.

I'm surprised you get as far as you do.

Your XML file is invalid -- the value of the 'name' attribute isn't quoted.

I'd suggest using Data::Dumper to print the structure that XMLin returned. (you've already loaded Data::Dumper, you might as well make use of it).

Sorry, it was mistyped in this form (i should've copy and pasted...). The name attribute is quoted in my xml file. So, the data in the dumped file is not that simple for me to read. How do I make sense of the following: $VAR1 = {
'host' => {
'jimmy.foo.com' => {
'hardware' => 'eht0', 'eht1' ,
'duty' => 'web'
},
The list goes on, but this is detailed info from one host. How do I make this useful. Thanks for being patient with me.

When you're posting code on here, you really should wrap your copy/pasted items with <code> ... </code>. I'm guessing you probably saw:

$VAR1 = {
     'host' => {
           'jimmy.foo.com' => {
                      'hardware' => ['eht0', 'eht1'],
                      'duty' => 'web'
           },
      },
};
[download]

So basically, you have a hash of hashes of hashes of something that might be an array. What you'll want to do is force them all to be an array (pass in ForceArray => [ qw(duty) ] to XMLin, or when you create a new XML::Simple object), or you'll have to check for each one:

my $hosts = $data->{'host'};
foreach my $host ( keys %$hosts ) {
    my $duties = $hosts->{$host}->{'duty'};
    print "$host : $_\n"
      foreach ( UNIVERSAL::isa( $duties, 'ARRAY' )
        ? @$duties
        : $duties );
}
[download]

<hosts>
  <host name="jimmy">
    <function>web</function>
    <function>dns</function>
    <location>miami</location>
  </host>
  <host name="haffa">
    <function>nfs</function>
    <function>quake</function>
    <location>hell</location>
  </host>
</hosts>
[download]

use XML::Simple;
use Data::Dumper;
# create object
my $xml = new XML::Simple ();
# read XML file
my $data = $xml->XMLin("/tmp/hosts.xml");
print Dumper($data);
[download]

$VAR1 = {
          'host' => {
                    'haffa' => {
                               'function' => [
                                             'nfs',
                                             'quake'
                                           ],
                               'location' => 'hell'
                             },
                    'jimmy' => {
                               'function' => [
                                             'web',
                                             'dns'
                                           ],
                               'location' => 'miami'
                             }
                  }
        };
[download]