XSLT newbie -- how to use the standard XPath functions?

I’ve been getting errors when using standard XPath functions such as “year-from-dateTime”.

Sample XSL (abridged):

<?xml version="1.0" encoding="ISO-8859-1"?>

<xsl:template match="/EDI_DC40_values">
<EDI_DC40 SEGMENT=“1”>

  <TABNAM>EDI_DC40</TABNAM>
  <MANDT>300</MANDT>
  <DOCNUM><xsl:value-of select="documentNo"/></DOCNUM>
  <DOCREL>700</DOCREL>
  <SNDPRN><xsl:value-of select="sender/partnerNumber"/></SNDPRN>
  <CREDAT>
 <xsl:value-of select="fn:year-from-dateTime(documentTimeStamp)"/>
 <xsl:value-of select="fn:month-from-dateTime(documentTimeStamp)"/>
 <xsl:value-of select="fn:day-from-dateTime(documentTimeStamp)"/>
  </CREDAT>

</EDI_DC40>
</xsl:template>

</xsl:stylesheet>

Using the above XSL results in the following error message:

Could not run 'testXsl'.

com.wm.app.b2b.server.ServiceException: [B2BXSL.0002.9003] JAXP: Error during transformation - com.wm.pkg.xslt.util.LocalizedTransformerException: [B2BXSL.0002.9001] JAXP: Fatal Error - java.lang.NoSuchMethodException: For extension function, could not find method org.apache.xpath.objects.XNodeSet.yearFromDateTime([ExpressionContext,] ).

Experimenting, I’ve hit the same type of error even when trying really “basic” functions like “substring”.

What should I do to resolve this? It looks like I need an updated Xalan JAR, but the latest one I downloaded doesn’t appear to have the required method…

Sorry about the format - trying again:

Error message is:

Could not run 'testXsl'.

com.wm.app.b2b.server.ServiceException: [B2BXSL.0002.9003] JAXP: Error during transformation - com.wm.pkg.xslt.util.LocalizedTransformerException: [B2BXSL.0002.9001] JAXP: Fatal Error - java.lang.NoSuchMethodException: For extension function, could not find method org.apache.xpath.objects.XNodeSet.yearFromDateTime([ExpressionContext,] ).

When experimenting, I’ve hit the same type of error even when trying really “basic” functions like “substring”. What should I do to resolve this? It looks like I need an updated Xalan JAR, but the latest one I downloaded doesn’t appear to have the required method…