Error messages when building webhelp

Hello all.

I am trying to build webhelp but keep getting error messages. Not even the webhelp test build does it's job. Any idea what is going on here? The docbook stylesheets are 1.76.1 and saxon 6.5.5 is installed as it should. Running ant with the "noclasspath" option does not help (as pointed out here http://docbook.sourceforge.net/release/xsl/current/webhelp/docs/content/ch02s01.html). Building webhelp fails with the following output:

Buildfile: /Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/webhelp/build.xml

validate:

clean:
   [delete] Deleting directory /Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/webhelp/test-ouput

chunk:
    [mkdir] Created dir: /Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/webhelp/test-ouput
     [xslt] Processing /Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/webhelp/docsrc/readme.xml to /Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/webhelp/test-ouput/dummy.html
     [xslt] Loading stylesheet /Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/webhelp/xsl/webhelp.xsl
     [xslt] : Warning! file:/Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/xhtml/autoidx.xsl: line 502: Attribute 'href' outside of element.
     [xslt] : Warning! file:/Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/xhtml/lists.xsl: line 728: Attribute 'type' outside of element.
[...]
     [xslt] : Error! null
     [xslt] Failed to process /Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/webhelp/docsrc/readme.xml

BUILD FAILED
/Users/brillo/Sites/tecdoc2/lib/docbook-xsl-1.76.1/webhelp/build.xml:34: javax.xml.transform.TransformerException: java.lang.NullPointerException
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:716)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:313)
	at org.apache.tools.ant.taskdefs.optional.TraXLiaison.transform(TraXLiaison.java:194)
	at org.apache.tools.ant.taskdefs.XSLTProcess.process(XSLTProcess.java:852)
	at org.apache.tools.ant.taskdefs.XSLTProcess.execute(XSLTProcess.java:388)
	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
	at org.apache.tools.ant.Task.perform(Task.java:348)
	at org.apache.tools.ant.Target.execute(Target.java:390)
	at org.apache.tools.ant.Target.performTasks(Target.java:411)
	at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
	at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
	at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
	at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
	at org.apache.tools.ant.Main.runBuild(Main.java:809)
	at org.apache.tools.ant.Main.startAnt(Main.java:217)
	at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
	at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
Caused by: java.lang.NullPointerException
	at com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary.referenceToNodeSet(BasisLibrary.java:998)
	at webhelp.l10n$dot$language()
	at webhelp.topLevel()
	at webhelp.transform()
	at com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet.transform(AbstractTranslet.java:603)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:709)
	... 21 more
---------
java.lang.NullPointerException
	at com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary.referenceToNodeSet(BasisLibrary.java:998)
	at webhelp.l10n$dot$language()
	at webhelp.topLevel()
	at webhelp.transform()
	at com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet.transform(AbstractTranslet.java:603)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:709)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:313)
	at org.apache.tools.ant.taskdefs.optional.TraXLiaison.transform(TraXLiaison.java:194)
	at org.apache.tools.ant.taskdefs.XSLTProcess.process(XSLTProcess.java:852)
	at org.apache.tools.ant.taskdefs.XSLTProcess.execute(XSLTProcess.java:388)
	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
	at org.apache.tools.ant.Task.perform(Task.java:348)
	at org.apache.tools.ant.Target.execute(Target.java:390)
	at org.apache.tools.ant.Target.performTasks(Target.java:411)
	at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
	at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
	at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
	at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
	at org.apache.tools.ant.Main.runBuild(Main.java:809)
	at org.apache.tools.ant.Main.startAnt(Main.java:217)
	at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
	at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)

Total time: 29 seconds

/frank