Unknown system function escape-uri()

xsl-list,

I am attempting to retrieve a document from a URL with the following
script and saxonhe9-2-0-3j.jar
I have done this before with URLs that do not contain characters such
as {*+ etc.

I am getting the error:

Error at xsl:variable on line 14 column 108 of page2.xsl:
  XPST0017: XPath syntax error at char 68 on line 14 in {...+named url
file*.xml',false...}:
    Unknown system function escape-uri()


I am surprised, because I use xpath functions very frequently, and I
am staring at the listing on page 773 of Michael Kay's XSLT 2.0 3rd
ed.
Could anyone suggest a remedy?

Regards,
Tim Lebo


<xsl:transform version="2.0"
               xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
               exclude-result-prefixes="">
<xsl:output method="xml" indent="yes" omit-xml-declaration="yes"/>

<xsl:template match="/">
   <xsl:variable name="url" select="escape-uri('http://files.com/my
poorly+named url file*.xml',false())"/>
   <xsl:variable name="webfile" select="doc($url)"/>
   <xsl:apply-templates select="$webfile/*"/>


   <!-- just to check that I can call default xpath functions -->
   <xsl:variable name="check-fn" select="distinct-values((4, 4, 5))"/>
   <xsl:for-each select="$check-fn">
      <xsl:value-of select="."/>
   </xsl:for-each>
</xsl:template>

</xsl:transform>