Running out of Memory

I use the attached template to collect all of the files in a given archieve
into a variable $all-chapters and each time the loop ran it would destory the
variable and I would use little memory. After processing a few 100 archieves I
run out of memory. Am I thinging about this correctly? Is there a more correct
way to do this?
Terry
Here is the template:
<xsl:templatename="main">
<xsl:result-documenthref="{concat($protocol , $base-out , '/' , $date ,
'_all-chapters_' , $book , '.txt')}"format="badger-1">
<!--
==================================================================== -->
<!--
use Java to get the list of files - not all version of Saxon will work -->
<xsl:variablename="dir"select="file:new(resolve-uri(concat('file:/' ,
$base-in)))"/>
<xsl:variablename="files"select="file:listFiles($dir)"/>
<xsl:for-eachselect="$files">
<xsl:variablename="uri-to-string">
<xsl:value-ofselect="."/>
</xsl:variable>
<xsl:variablename="file-name"select="subsequence(reverse(tokenize($uri-to-str
ing, '\\')), 1, 1)"/>
<!-- process the selected book or All -->
<xsl:variablename="all-chapters">
<xsl:variablename="chapter"select="$file-name"/>
<xsl:variablename="document"select="doc(concat($jar-protocol , $base-in ,
$file-name , '!' , '/designmap.xml'))"/>
<xsl:elementname="chapter">
<xsl:attributename="name"select="$chapter"/>
<xsl:copy-ofselect="$document"/>
<xsl:elementname="MasterSpreads-all">
<xsl:for-eachselect="$document/Document/idPkg:MasterSpread/@src">
<xsl:copy-ofselect="doc(concat($jar-protocol , $base-in , $file-name , '!/' ,
.))"/>
</xsl:for-each>
</xsl:element>
<xsl:elementname="Spreads-all">
<xsl:for-eachselect="$document/Document/idPkg:Spread/@src">
<xsl:copy-ofselect="doc(concat($jar-protocol , $base-in , $file-name , '!/' ,
.))"/>
</xsl:for-each>
</xsl:element>
<xsl:elementname="Stories-all">
<xsl:for-eachselect="$document/Document/idPkg:Story/@src">
<xsl:copy-ofselect="doc(concat($jar-protocol , $base-in , $file-name , '!/' ,
.))"/>
</xsl:for-each>
</xsl:element>
</xsl:element>
</xsl:variable>
<!-- the
work is done here -->
<!-- <xsl:apply-templates select="$all-chapters"/>-->
</xsl:for-each>
</xsl:result-document>
</xsl:template>