#!usr/bin/perl
use XML::Checker::Parser;

my $xp = new XML::Checker::Parser ( Handlers => { } );
eval {
 $xp->parsefile("Invoice.xml");
};
if ($@) {
  # ... your error handling code here ...
  print "Invoice.xml failed validation!\n";
  die "$@";
}
print "Invoice.xml passed validation\n";