Causes for fckstyles.xml to not be processed?

The styles drop-down is populated. According to the documentation in fckstyles.xml, that's as expected, since the core styles are hard-coded. I'll attach a screen-shot.

Here's the fckstyles.xml file I'm trying to load. The stuff I've added is at the end. However, none of the stuff at the beginning will show up either -- that's the demo stuff, that's there by default. If I understand the code documentation properly, it should.

<?xml version="1.0" encoding="utf-8" ?>
<!--
 * FCKeditor - The text editor for Internet - http://www.fckeditor.net
 * Copyright (C) 2003-2008 Frederico Caldeira Knabben
 *
 * == BEGIN LICENSE ==
 *
 * Licensed under the terms of any of the following licenses at your
 * choice:
 *
 *  - GNU General Public License Version 2 or later (the "GPL")
 *    http://www.gnu.org/licenses/gpl.html
 *
 *  - GNU Lesser General Public License Version 2.1 or later (the "LGPL")
 *    http://www.gnu.org/licenses/lgpl.html
 *
 *  - Mozilla Public License Version 1.1 or later (the "MPL")
 *    http://www.mozilla.org/MPL/MPL-1.1.html
 *
 * == END LICENSE ==
 *
 * This is the sample style definitions file. It makes the styles combo
 * completely customizable.
 *
 * See FCKConfig.StylesXmlPath in the configuration file.
-->
<Styles>

   <!-- Block Styles -->

   <!--
   # These styles are already available in the "Format" combo, so they are not
   # needed here by default.

   <Style name="Heading 1" element="h1" />
   <Style name="Heading 2" element="h2" />
   <Style name="Heading 3" element="h3" />
   <Style name="Heading 4" element="h4" />
   <Style name="Heading 5" element="h5" />
   <Style name="Heading 6" element="h6" />
   <Style name="Paragraph" element="p" />
   <Style name="Document Block" element="div" />
   <Style name="Preformatted Text" element="pre" />
   <Style name="Address" element="address" />
   -->

   <!-- Inline Styles -->

   <!--
   # These are core styles available as toolbar buttons.

   <Style name="Bold" element="b">
      <Override element="strong" />
   </Style>
   <Style name="Italic" element="i">
      <Override element="em" />
   </Style>
   <Style name="Underline" element="u" />
   <Style name="Strikethrough" element="strike" />
   <Style name="Subscript" element="sub" />
   <Style name="Superscript" element="sup" />
   -->

   <Style name="Marker: Yellow" element="span">
      <Style name="background-color" value="Yellow" />
   </Style>
   <Style name="Marker: Green" element="span">
      <Style name="background-color" value="Lime" />
   </Style>

   <Style name="Big" element="big" />
   <Style name="Small" element="small" />
   <Style name="Typewriter" element="tt" />

   <Style name="Computer Code" element="code" />
   <Style name="Keyboard Phrase" element="kbd" />
   <Style name="Sample Text" element="samp" />
   <Style name="Variable" element="var" />

   <Style name="Deleted Text" element="del" />
   <Style name="Inserted Text" element="ins" />

   <Style name="Cited Work" element="cite" />
   <Style name="Inline Quotation" element="q" />

   <Style name="Language: RTL" element="span">
      <Attribute name="dir" value="rtl" />
   </Style>
   <Style name="Language: LTR" element="span">
      <Attribute name="dir" value="ltr" />
   </Style>
   <Style name="Language: RTL Strong" element="bdo">
      <Attribute name="dir" value="rtl" />
   </Style>
   <Style name="Language: LTR Strong" element="bdo">
      <Attribute name="dir" value="ltr" />
   </Style>

   <!-- Object Styles -->

   <Style name="Image on Left" element="img">
      <Attribute name="style" value="padding: 5px; margin-right: 5px" />
      <Attribute name="border" value="2" />
      <Attribute name="align" value="left" />
   </Style>
   <Style name="Image on Right" element="img">
      <Attribute name="style" value="padding: 5px; margin-left: 5px" />
      <Attribute name="border" value="2" />
      <Attribute name="align" value="right" />
   </Style>
   
   <Style name="Quote" element="p">
      <Attribute name="class" value="quote" />
   </Style>
   <Style name="Quote" element="div">
      <Attribute name="class" value="quote" />
   </Style>
   <Style name="Quote Attribution" element="p">
      <Attribute name="class" value="quote-attribution" />
   </Style>
   <Style name="Quote Attribution" element="div">
      <Attribute name="class" value="quote-attribution" />
   </Style>
   
</Styles>

Screen shots are from FF3 in OS X, but they look the same in IE7 on Windows XP. The cursor is placed within a paragraph container for this screenshot.

This is the dev site for a client and I'm on a tight deadline, so I can't easily send a demo link. But I can provide any Firebug output that's useful, if you tell me what you want to see.