Ant XSLT task error

[Eric Johnson <eric.johnson@iona.com>]

I'm trying to use the Ant xslt task to build a docbook book and I get
the following errors:

     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/autoidx.xsl: line 420:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/autoidx.xsl: line 457:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/autoidx.xsl: line 480:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/callout.xsl: line 98:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/xref.xsl: line 170:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/xref.xsl: line 919:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/inline.xsl: line 77:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/inline.xsl: line 117:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/inline.xsl: line 141:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/inline.xsl: line 659:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/inline.xsl: line 870:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/inline.xsl: line 987:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/inline.xsl: line 1118:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/inline.xsl: line 1218:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/glossary.xsl: line 296:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/glossary.xsl: line 358:
Attribute 'href' outside of element.
     [xslt] : Error!
file:/home/emjohnson/dbck/lib/docbook-xsl/xhtml/annotations.xsl: line
106: Attribute 'onClick' outside of element.
     [xslt] : Error! The first argument to the non-static Java function
'highlight' is not a valid object reference.
     [xslt] : Error! Error checking type of the expression
'com.sun.org.apache.xalan.internal.xsltc.compiler.ApplyTemplates@ad8659'.
     [xslt] : Fatal Error! Could not compile stylesheet

Any ideas about what I've missed?
Thanks,
Eric