Getting an error with a variable

Hi all

I have some code which is causing me grief, and my experience isnt enough to
figure it out. I have the code below. The last line creates an error:

msxml3.dll error '80004005'
A reference to variable or parameter 'sNum' cannot be resolved. The variable
or parameter may not be defined, or it may not be in scope.

If I remove the line it works fine. Would someone like to suggest how I can
use the variable.

Thanks
Garry

=============================================
<xsl:choose>
  <xsl:when test="0=$paramVal4">
       <xsl:for-each select="/stages/competition/itinerary/stage[1]">
	      <xsl:variable name="sNum">
	        <xsl:value-of select="@no"/>
	      </xsl:variable>
       </xsl:for-each>
  </xsl:when>

  <xsl:otherwise>
	<xsl:variable name="sNum">
	    <xsl:value-of select="$paramVal2"/>
	</xsl:variable>
  </xsl:otherwise>
</xsl:choose>

<h2><xsl:value-of select="$sNum" /></h2>  <--- causes error