[help-texinfo] wrong xml output

[Ferenc Wagner]

               Hi,

Working with version 4.6 from Debian unstable,
makeinfo --xml produced the following structure:

[...]
</heading>
  <heading>
   <title>See also
</title>


   <para>
Internals: <internalsref href="NoteEvent">NoteEvent</internalsref>
<indexterm index="cp">NoteEvent</indexterm>, and <internalsref 
href="NoteHead">NoteHead</internalsref>
<indexterm index="cp">NoteHead</indexterm>.
   </para>
</node>
  <node>
   <nodename>Chromatic alterations</nodename>
[...]

which has a <heading> ... </node> start-end mismatch.  The
source is a rather convoluted and long piece of art.  I
couldn't reproduce the same problem with a short input file
with reasonable effort, so decided to ask if the above rings
any bells before furhter struggling.  Can you prehaps
recommend some place to look at?  I compiled texinfo myself,
but don't know much about the system.  The sources are
available at <http://afavant.elte.hu/~wferi/lilypond/texi/>,
the master file is lilypond.texi.
-- 
Thanks for your attention,
Feri.