Xalan ESLT function date:date-add

[gerritjan]

Hello,

This XSLT:
<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:date="http://exslt.org/dates-and-times"
extension-element-prefixes="date xsl" >
<xsl:import href="date.add.function.xsl" />
<xsl:output method="xml"/>
<xsl:param name="p_dagen_terug"/>

<xsl:template match="onderwerpen">
<xsl:variable name="d1"><xsl:value-of select="date:date()"/></xsl:variable>
<xsl:variable name="d2"><xsl:value-of select="substring-before ($d1, '+02:00')"/></xsl:variable>
<xsl:variable name="d5"><xsl:value-of select="date:date-add($d2,'-P50D')"/></xsl:variable>
<basis>
1
<xsl:value-of select="$d1"/>
2
<xsl:value-of select="$d2"/>
5
<xsl:value-of select="$d5"/>
</basis>
</xsl:template>


</xsl:stylesheet>
<x-tad-bigger>
Gives this error;
org.apache.cocoon.ProcessingException: Failed to execute pipeline.: java.lang.RuntimeException: java.lang.RuntimeException: java.lang.NullPointerException

</x-tad-bigger>I'm not sure if Xalan supports this EXSLT function natively , but with 'import' I was hoping to use this EXSLT function anyway
by the way: without the 'import' line I get the same error...
The 'imported' file is downloadable from www.exslt.org

Gerritjan Koekkoek