DOCBOOK: Tertiaryie Error

[Todd Babinski <todd dot babinski at dynetics dot com>]

Hello,

I am using DocBook v4.1 (SGML) with v1.57 of the stylesheets.  I am
working on a document and am constructing the index by hand since I do
not want to rely on having Perl installed on every machine in order to
construct the index.  All was going well until I got an odd error and I
cannot figure out what is going wrong.

Here is a sample of what I have:
    <indexentry>
      <primaryie>Commands</primaryie>
        <secondaryie>Help Stuff, see <xref
linkend="hmcommands"></secondaryie> 
          <tertiaryie>activate, see <xref
linkend="activatep"></tertiaryie>
       ...

The error I am getting for the tertiaryie line is the message:
	xref to COMMAND unsupported

In the above example, the secondarie line works just fine and appears
like you would expect it to.  The tertiaryie is not, however.

I'm the index using xref so that I don't have to litter my document with
indexterm tags.  Instead I am linking to the id names for sections,
tables, etc.  After abusing the stylesheets some, the output looks good
for my print and HTML purposes.

Any thoughts on what is wrong or how to fix this?

Thanks
Todd Babinski