Renew pestilence DK Wotlk

Hello, what would be the correct implementation of pestilence? It doesn't work for me.

    <FightClassSpell>
      <FightClassConditions>
        <FightClassCondition>
          <ContionType>IsSpellUsable</ContionType>
          <Param xsi:type="FightClassConditionStringBool">
            <Name>Pestilence</Name>
            <Need>true</Need>
          </Param>
        </FightClassCondition>
        <FightClassCondition>
          <ContionType>TargetBuffCastedByMe</ContionType>
          <Param xsi:type="FightClassConditionStringBool">
            <Name>Frost Fever</Name>
            <Need>true</Need>
          </Param>
        </FightClassCondition>
        <FightClassCondition>
          <ContionType>TargetBuffCastedByMe</ContionType>
          <Param xsi:type="FightClassConditionStringBool">
            <Name>Blood Plague</Name>
            <Need>true</Need>
          </Param>
        </FightClassCondition>
        <FightClassCondition>
          <ContionType>BuffTimeLeftTarget</ContionType>
          <Param xsi:type="FightClassConditionBuffStack">
            <Number>4</Number>
            <Type>SmallerOrEqual</Type>
            <Name>Frost Fever</Name>
          </Param>
        </FightClassCondition>
      </FightClassConditions>
      <SpellName>Pestilence</SpellName>
      <Priority>13</Priority>
      <IsBuff>true</IsBuff>
      <DescriptionSpell>Pestilence</DescriptionSpell>
    </FightClassSpell>