I recently ran in to several records can not be displayed, it turned
out that it has to do with the following related bugs in the XML
parser which XML/Unserializer.php rely on.
If you have & or < or > etc... in your marc records, you may have run
into this bug, took us a while to track this down. Instead of
downgrade/upgrade your libxml2/php/apache stack, you can simply add
<xsl:output method="xml" indent="yes" cdata-section-