To get a better idea of what your data structure looks like you should use Data::Dump or Data::Dumper.

my $xmlfile = new XML::Simple (Outputfile => $conf,
                     ForceArray => 1,
                                RootName=>'exec');
my $xml = $xmlfile->XMLin($conf);

use Data::Dump qw(dump);
print "XML => " . dump( $xml );
[download]

This should be a good starting point to see what you are working with.