为什么XML：Simple抱怨“找不到元素”？

no element found at line 15,column 0,byte 308 at /usr/lib/perl5/vendor_perl/5.8.0/i386-linux-thread-multi/XML/Parser.pm line 185

XML文件如下：

<?xml version="1.0"?>
<customer-data>
<customer>
<first_name>Frank</first_name>
<last_name>Sanbeans</last_name>
<dob>3/10</dob>
<email>frank@example.com</email>
</customer>
<customer>
<first_name>Sandy</first_name>
<last_name>Sanbeans</last_name>
<dob>4/15</dob>
<email>sandy@example.com</email>
</customer>

而且,我的perl代码是：

use strict;
use XML::Simple;

my $xml = XMLin('./test.xml',forcearray => 1);
foreach my $customer (@{$xml->{customer}}) {
  print "Name: $customer->{first_name}->[0] ";
  print "$customer->{last_name}->[0]n";
  print "Birthday: $customer->{dob}->[0]n";
  print "E-mail Address: $customer->{email}->[0]n";
}

怎么解决这个问题？

谢谢.