> <HesaValidate_Response xmlns="http://HesaValidateSqlSend">

your xml is in the namespace "http://HesaValidateSqlSend"

> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
> version="1.0">
>    <xsl:template match="/">
>        <xsl:variable name="RowCount" select="count(//row)"/>

you need to give that namespace a prefix in your stylesheet and use that:

<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:h="http://HesaValidateSqlSend"
    exclude-result-prefixes="h">

  <xsl:template match="/">
     <xsl:value-of select="count(//h:row)"/>



cheers
-- 
Andrew Welch
http://andrewjwelch.com
Kernow: http://kernowforsaxon.sf.net/