Description:
------------
A simple xslt stylesheet used on a production website with php 5.0.4 doesn't work more since we installed php 5.1.2.?

Reproduce code:
---------------
PHP code:

public function loadXslFile(filewrapper $xslFile) {
		
	$this->xslDom->load( $xslFile->getFileName() );
	$this->xslProcessor->importStylesheet( $this->xslDom );
				
}

XSLT file:

<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="ISO-8859-1" indent="yes" omit-xml-declaration="yes" />
<xsl:strip-space elements="*" />
<xsl:param name="current"/>
	<xsl:template match="node[@id=$current]">
			<xsl:if test="not(@id='home')">
				:: <xsl:value-of select="@title" />					
			</xsl:if>
	</xsl:template>
</xsl:stylesheet>

Expected result:
----------------
The XSLT is expected to return the title attribute of a node element which id matches 'current' param value.

Actual result:
--------------
We obtain the message:

XSLTProcessor::importStylesheet() [function.importStylesheet]: Undefined variable

Trying to extend the scope of xsl:param to enclose the whole template will result in:

XSLTProcessor::importStylesheet() [function.importStylesheet]: compilation error: file D:/InetPub/wwwroot/www.uniroma3.it/xml/pagetitle.xsl line 6 element template