xsl:if : getting dcxjp to parse expr commands

I am using the canned example XMLtoHTML.java from the xdev.datachannel.com site and it works great for simple xml/xsl files, but when I have:

<xsl:if expr="(childNumber(this) % 4) == 1">

in my xsl file it produces the error:

Must specify test pattern in <xsl:if>

it seems to ignore the expr="(childNumber(this) % 4) == 1"  bit.  This worked while using the XMLDOM component from MS. Does anyone know why it won't work with dcxjp?

thanks

Jason Classon