[fiona86]

Hi thanks for the reply. I'm still running into this problem I've included some of the content.opf file below, if anyone has suggestions of how this error can be solved I'd be so grateful!

<?xml version="1.0"  encoding="UTF-8"?>
<package xmlns="http://www.idpf.org/2007/opf" version="2.0" unique-identifier="uuid_id">
  <metadata xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:opf="http://www.idpf.org/2007/opf" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:calibre="http://calibre.kovidgoyal.net/2009/metadata" xmlns:dc="http://purl.org/dc/elements/1.1/">
    <dc:creator opf:role="aut" opf:file-as="author">author</dc:creator>
<dc:creator opf:role="aut">authorl</dc:creator>
<dc:publisher>Publishers</dc:publisher>
    <meta name="calibre:series_index" content="1"/>
    <meta name="calibre:rating" content="10"/>
    <dc:description></dc:description>
    <dc:language>en</dc:language>
    <meta name="calibre:timestamp" content="2011-06-23T11:44:51.909390+00:00"/>
    <dc:title opf:file-as="title">title</dc:title>
    <meta name="cover" content="cover"/>
    <dc:date>2011-06-22T23:00:00+00:00</dc:date>
    <dc:contributor opf:role="bkp">calibre (0.7.28) [http://calibre-ebook.com]</dc:contributor>
    <dc:identifier opf:scheme="ISBN"></dc:identifier>
    <dc:identifier id="uuid_id" opf:scheme="uuid">8e4153bb-af45-4260-8c4a-ea80f95a4c2f</dc:identifier>
    <dc:subject>Thailand</dc:subject>

When I remove the code "opf:file-as" the error still occurs...