5.1b2 xsd schema invalid with xmllint?

Hi, I'm using the 5.1b2 xsd with xmllint. Trying to validate one of the
example topics from the V1.3 Guide nets me this:

[jwulf@gaura Docbook_5]$ xmllint --schema
/usr/share/xml/docbook5/schema/xsd/5.1b2/assembly.xsd docbook5_topic.xml
/usr/share/xml/docbook5/schema/xsd/5.1b2/assembly.xsd:16793: element
complexType: Schemas parser error : local complex type: The content
model is not determinist.
/usr/share/xml/docbook5/schema/xsd/5.1b2/assembly.xsd:17701: element
complexType: Schemas parser error : local complex type: The content
model is not determinist.
/usr/share/xml/docbook5/schema/xsd/5.1b2/assembly.xsd:17722: element
complexType: Schemas parser error : local complex type: The content
model is not determinist.
WXS schema /usr/share/xml/docbook5/schema/xsd/5.1b2/assembly.xsd failed
to compile
<?xml version="1.0"?>
<topic xmlns="http://docbook.org/ns/docbook" version="5.1">
<info>
  <title>Troubleshooting</title>
</info>

<para>If your <citetitle>Joo Janta 200 Super-Chromatic Peril Sensitive
Sunglasses</citetitle> become opaque, do not be alarmed. That's more
or less the point.</para>

</topic>


DTD validation seems to work fine:
[jwulf@gaura Docbook_5]$ xmllint --dtdvalid
/usr/share/xml/docbook5/schema/dtd/5.1b2/docbook.dtd docbook5_topic.xml
<?xml version="1.0"?>
<topic xmlns="http://docbook.org/ns/docbook" version="5.1">
<info>
  <title>Troubleshooting</title>
</info>

<para>If your <citetitle>Joo Janta 200 Super-Chromatic Peril Sensitive
Sunglasses</citetitle> become opaque, do not be alarmed. That's more
or less the point.</para>

</topic>