Namespace 'http://exslt.org/regexp' does not contain any functions.

I was looking through the archives and found a question raising this
issue but no response.  I am using MSXML4 processor (as part of
Marrowsoft's XSelerator, but it does the same thing from explorer and
Altova's XMLSpy) and I get the following above error with the following
style sheet. I haven't got to the point where I can even test the actual
regular expression; the output crashes with the above error as soon as
it hits the regexp code.

Any assistance greatly appreciated.. 

Craig Dunstan

The stylesheet nessus.xslt is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet 
	version="1.0" 
	xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
	xmlns:regexp="http://exslt.org/regexp" 
	extension-element-prefixes="regexp">

	<xsl:import href="c:\exslt\regexp\regexp.xsl" />
	
	<xsl:output method="xml" version="1.0" encoding="UTF-8"
indent="yes"/>
	

	<xsl:template match="/">
		<table border="1">
			<tbody>
				<xsl:apply-templates
select="report/results/result/ports/port">
					<xsl:sort select="@protocol"/>

					<xsl:sort select="@portid"
data-type="number"/>				
				</xsl:apply-templates>
			</tbody>
		</table>
	</xsl:template>
	
	<xsl:template match="port">
		<tr valign="top">
			<td><xsl:value-of select="information/id"/></td>

			<xsl:choose>
				<xsl:when test="@portid">
					<td><xsl:value-of
select="service/@name"/>(<xsl:value-of
select="@protocol"/>/<xsl:value-of select="@portid"/>)</td>

				</xsl:when>
				<xsl:otherwise>
					<td><xsl:value-of
select="service/@name"/></td>			
				</xsl:otherwise>
			</xsl:choose>
			<td><xsl:value-of
select="information/data"/></td>			
			<td><xsl:value-of
select="information/severity"/></td>	
			<td><xsl:value-of
select="regexp:match(information/description, 'risk factor :
(low|high)', 'i')"/></td>		
		</tr>
	</xsl:template>
	
</xsl:stylesheet>