what you can do:

  <xsl:param name="nodeValue">something</xsl:param>
    <xsl:param name="valueSearch">false</xsl:param>
       <xsl:choose>
         <xsl:when test="$valueSearch='false'">
            <xsl:variable name="initialResult"
   select="/one/two[three/four[contains(text(),$nodeValue)]]"/>
         </xsl:when>


There is no point declaring a variable there 
as it will go out of scope at the </xsl:when>  also 
this is at the top level of a stylesheet (where xsl:choose is not
allowed)


David


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