I've created a custom citation style for Biomed Central journals. I've tested it by pasting it into the CSL edit page:
chrome://zotero/content/tools/csledit.xul

It looks okay at this point.

Next, I install it using drag-and-drop. It asks me if I want to install, and says that it installs successfully.

After installing, I refresh the CSL, and can select "BioMed Central Journals" in the pulldown box.

The box reads:
"false"

That's it. And the style dosen't work from documents.

Any ideas what I am doing wrong?

Thanks very much!
Charles Danko

The custom CSL file I am trying to install is here:
<?xml version="1.0" encoding="UTF-8"?>
<?oxygen RNGSchema="http://xbiblio.svn.sourceforge.net/viewvc/*checkout*/xbiblio/csl/schema/trunk/csl.rnc" type="compact"?>
<style xmlns="http://purl.org/net/xbiblio/csl" class="in-text" xml:lang="en">
<info>
<title>BioMed Central Journals</title>
<author>
<name>Charles Danko</name>
<email>dankoc@gmail.com</email>
</author>
<category term="biology"/>
<category term="numeric"/>
<updated>2008-11-03T02:05:41+00:00</updated>
</info>
<macro name="author">
<names variable="author">
<name sort-separator=" " delimiter=", " initialize-with="" delimiter-precedes-last="yes" name-as-sort-order="all" suffix=":"/>
</names>
</macro>
<macro name="editor">
<names variable="editor">
<name initialize-with="." delimiter=", " and="text" name-as-sort-order="all"/>
<label form="short" prefix=", " text-case="lowercase" suffix="."/>
</names>
</macro>
<macro name="title">
<choose>
<if type="book">
<text variable="title" font-style="bold"/>
</if>
<else>
<text variable="title" font-weight="bold"/>
</else>
</choose>
</macro>
<macro name="publisher">
<text variable="publisher" font-style="italic" suffix=" "/>
<date variable="issued">
<date-part name="year" suffix=", "/>
</date>
<text variable="volume"/>
</macro>
<macro name="access">
<text variable="URL"/>
</macro>
<macro name="page">
<group>
<text variable="page"/>
</group>
</macro>
<citation>
<option name="collapse" value="citation-number"/>
<sort>
<key variable="citation-number"/>
</sort>
<layout prefix="[" suffix="]" delimiter=",">
<text variable="citation-number"/>
</layout>
</citation>
<bibliography>
<option name="et-al-min" value="100"/>
<option name="et-al-use-first" value="1"/>
<option name="second-field-align" value="true"/>
<layout suffix=".">
<text variable="citation-number" prefix="" suffix="."/>
<text macro="author" prefix=" " suffix=", "/>
<choose>
<if type="book">
<group delimiter=" ">
<text macro="title"/>
<text macro="publisher"/>
</group>
</if>
<else-if type="chapter">
<group delimiter=" ">
<text macro="title"/>
<text variable="container-title" font-style="italic"/>
<text macro="editor"/>
<text macro="publisher"/>
<text macro="page"/>
</group>
</else-if>
<else>
<group delimiter=" ">
<text macro="title" suffix="."/>
<text variable="container-title" font-style="italic"/>
<date variable="issued" suffix=",">
<date-part name="year"/>
</date>
<text variable="issue" font-weight="bold" suffix=":"/>
<text macro="page"/>
</group>
</else>
</choose>
<text macro="access" prefix="; "/>
</layout>
</bibliography>
</style>