sub validateXML {
    my ($xmlfile, $xsdfile) = @_;
    my $parser = XML::LibXML->new (XML_LIBXML_LINENUMBERS => 1 );
   
    my $doc = $parser->parse_file ("$xmlfile");
    my $schema = XML::LibXML::Schema->new( location => "$xsdfile" );

    eval { $schema->validate($doc) };
    return $@;
}