<table cellSpacing="0" cellPadding="0" width="93%" align="center" border="0">
    <xsl:for-each select="rss/channel/item">
    <xsl:if test="position() &gt;5&amp;position() &lt;12">
    <xsl:variable name="sUrl" select="link"/>
      <tr>
        <td height="12">
          ●<a href="{$sUrl}"><xsl:value-of select="substring(PublishTitle,0,15)"/></a>
        </td>
      </tr>
  </xsl:if>
  </xsl:for-each>
  </table>出现这样的错误:boolean(position() >5&position() <12)”具有无效的标记,怎么办呢?