[xsl] position()!=last() works in one env, not in another

I am testing in Altova XMLSpy and running in PHP5.  In XMLSpy the
position()!=last() works fine, but in PHP5, it is always true.  Here
is the code:

 <xsl:template match="p:category|p:subCategory|p:imageDir" mode="menu">
   <xsl:choose>
		<xsl:when test="@objectID=$objectID"><xsl:value-of select="@name"/></xsl:when>
		<xsl:otherwise><a href="{$self}?fldoid={@objectID}"><xsl:value-of
select="@name"/></a></xsl:otherwise>
	</xsl:choose>
	<xsl:if test="position()!=last()"><xsl:text
disable-output-escaping="yes">&amp;nbsp;|&amp;nbsp;</xsl:text></xsl:if>
 </xsl:template>