I have a macro that is meant to randomly select an image for a page from a folder specified as a parameter.

The problem is that the getMedia doesn't always return a value, which it did previously.  Can anyone see what's wrong here?

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xsl:stylesheet [
  <!ENTITY nbsp "&#x00A0;">
]>
<xsl:stylesheet
  version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:msxml="urn:schemas-microsoft-com:xslt"
  xmlns:umbraco.library="urn:umbraco.library" xmlns:Exslt.ExsltCommon="urn:Exslt.ExsltCommon" xmlns:Exslt.ExsltDatesAndTimes="urn:Exslt.ExsltDatesAndTimes" xmlns:Exslt.ExsltMath="urn:Exslt.ExsltMath" xmlns:Exslt.ExsltRegularExpressions="urn:Exslt.ExsltRegularExpressions" xmlns:Exslt.ExsltStrings="urn:Exslt.ExsltStrings" xmlns:Exslt.ExsltSets="urn:Exslt.ExsltSets"
  exclude-result-prefixes="msxml
 umbraco.library Exslt.ExsltCommon Exslt.ExsltDatesAndTimes 
Exslt.ExsltMath Exslt.ExsltRegularExpressions Exslt.ExsltStrings 
Exslt.ExsltSets ">

  <xsl:output method="xml" omit-xml-declaration="yes"/>
  <xsl:param name="currentPage"/>
  <xsl:variable name="folderNodeID" select="/macro/randomImage"/>
  <xsl:variable name="debug" select="0"/>

  <xsl:template match="/">

    <xsl:if test="$debug=1">
      <xsl:comment>
        folderNodeID <xsl:value-of select="$folderNodeID"/>        
      </xsl:comment>
    </xsl:if>


    <xsl:choose>
      <xsl:when test="$folderNodeID &gt; 0">
        <xsl:variable name="randomImageNumber" select="ceiling( Exslt.ExsltMath:random() * (count(umbraco.library:GetMedia($folderNodeID, 1)/Folder/Image) ) )"/>
        <xsl:choose>
          <xsl:when test="$randomImageNumber &gt; 0">
            <img src="{umbraco.library:GetMedia($folderNodeID, 1)/Folder/Image[$randomImageNumber]/umbracoFile}" />  
          </xsl:when>
          <xsl:otherwise>
            <xsl:comment>folderNodeId lt= 0</xsl:comment>
            <xsl:call-template name="drawFromDefault" />
          </xsl:otherwise>
        </xsl:choose>

      </xsl:when>
      <xsl:otherwise>
        <xsl:comment>
          Folder Id was not provided.
        </xsl:comment>
        <xsl:call-template name="drawFromDefault" />
      </xsl:otherwise>
    </xsl:choose>
  </xsl:template>

  <xsl:template name="drawFromDefault">
    <xsl:variable name="folderNodeID" select="1216"/>
    <xsl:if test="$debug=1">
      <xsl:comment>
        using default folderNodeID <xsl:value-of select="$folderNodeID"/>        
      </xsl:comment>
    </xsl:if>
    <xsl:variable name="randomImageNumber" select="ceiling( Exslt.ExsltMath:random() * (count(umbraco.library:GetMedia($folderNodeID, 1)/Folder/Image) ) )"/>
    <xsl:if test="$randomImageNumber &gt; 0">
      <img src="{umbraco.library:GetMedia($folderNodeID, 1)/Folder/Image[$randomImageNumber]/umbracoFile}" />
    </xsl:if>
  </xsl:template>
</xsl:stylesheet>