The following script

#!/usr/bin/perl --
use strict;
use warnings;

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

my $file = "test.xml";
my $xs1 = XML::Simple->new();
my $doc = $xs1->XMLin($file, keyattr=>['CLASSNAME'], ForceContent=>1, 
+ForceArray=>1);

print Dumper($doc);

foreach my $element (keys %{$doc->{INNERSUB}->{INNERSUB1}}) {
        print "$element\n";
        print "\tType:\t$doc->{INNERSUB}->{INNERSUB1}->{$element}[0]->
+{Type}\n";
        print "\tContent:\t$doc->{INNERSUB}->{INNERSUB1}->{$element}[0
+]->{content}\n";
}
exit(0);
[download]

With test.xml containing:

<SUB CLASSNAME="SUB1">
   <INNERSUB CLASSNAME="INNERSUB1">
        <Element1 Type="Type1">Content</element1>
        <Element2 Type="Type2">Content</element2>
   </INNERSUB>
</SUB>
[download]

Produces

$VAR1 = {
          'INNERSUB' => {
                        'INNERSUB1' => {
                                       'Element2' => [
                                                     {
                                                       'Type' => 'Type
+2',
                                                       'content' => 'C
+ontent'
                                                     }
                                                   ],
                                       'Element1' => [
                                                     {
                                                       'Type' => 'Type
+1',
                                                       'content' => 'C
+ontent'
                                                     }
                                                   ]
                                     }
                      },
          'CLASSNAME' => 'SUB1'
        };
Element2
        Type:   Type2
        Content:        Content
Element1
        Type:   Type1
        Content:        Content
[download]

Update: If the syntax for accessing nested data structures is not familiar, you might have a look at perlreftut.