Plz can you tell me why my code don't work server error on loading
<configs>
<append xpath="/blocks/block[@name=rScrapIronLogSpike5]">
<property class="UpgradeBlock">
<property name="ToBlock" value="ConcreteLogSpike7"/>
<property name="Item" value="resourceConcreteMix"/>
<property name="ItemCount" value="10"/>
<property name="UpgradeHitCount" value="4"/>
</property>
<property name="DowngradeBlock" value="rScrapIronLogSpike"/>
</append>
<append xpath="/blocks/block[@name=steelLogSpike6]">
<property class="UpgradeBlock">
<property name="ToBlock" value="FireSteelLogSpike"/>
<property name="Item" value="ammoGasCan"/>
<property name="ItemCount" value="25"/>
<property name="UpgradeHitCount" value="4"/>
</property>
<property name="DowngradeBlock" value="ConcreteLogSpike7"/>
</append>
<append xpath="/blocks">
<block name="ConcreteLogSpike7">
<property name="CreativeMode" value="Dev"/>
<property name="Damage" value="7"/>
<property name="Damage_received" value="10"/>
<property name="Texture" value="315"/>
<property name="ImposterExchange" value="imposterPyramid" param1="110"/>
<property class="RepairItems"> <property name="resourceConcreteMix" value="10"/> </property>
<property class="UpgradeBlock">
<property name="ToBlock" value="steelLogSpike6"/>
<property name="Item" value="resourceForgedSteel"/>
<property name="ItemCount" value="10"/>
<property name="UpgradeHitCount" value="4"/>
</property>
<property name="DowngradeBlock" value="rScrapIronLogSpike5"/>
</block>
<block name="FireSteelLogSpike">
<property name="Extends" value="steelLogSpike6"/>
<property name="CreativeMode" value="Dev"/>
<property name="Damage" value="7"/>
<property name="Damage_received" value="10"/>
<property name="Texture" value="346,345,341,345,262,345"/>
<property name="ImposterExchange" value="imposterPyramid" param1="110"/>
<property name="DowngradeBlock" value="steelLogSpike6"/>
<property class="RepairItems"> <property name="ammoGasCan" value="25"/> </property>
</block>
</append>
</configs>
i add Condrete Spike And Fire Steel Spike
<configs>
<append xpath="/blocks/block[@name=rScrapIronLogSpike5]">
<property class="UpgradeBlock">
<property name="ToBlock" value="ConcreteLogSpike7"/>
<property name="Item" value="resourceConcreteMix"/>
<property name="ItemCount" value="10"/>
<property name="UpgradeHitCount" value="4"/>
</property>
<property name="DowngradeBlock" value="rScrapIronLogSpike"/>
</append>
<append xpath="/blocks/block[@name=steelLogSpike6]">
<property class="UpgradeBlock">
<property name="ToBlock" value="FireSteelLogSpike"/>
<property name="Item" value="ammoGasCan"/>
<property name="ItemCount" value="25"/>
<property name="UpgradeHitCount" value="4"/>
</property>
<property name="DowngradeBlock" value="ConcreteLogSpike7"/>
</append>
<append xpath="/blocks">
<block name="ConcreteLogSpike7">
<property name="CreativeMode" value="Dev"/>
<property name="Damage" value="7"/>
<property name="Damage_received" value="10"/>
<property name="Texture" value="315"/>
<property name="ImposterExchange" value="imposterPyramid" param1="110"/>
<property class="RepairItems"> <property name="resourceConcreteMix" value="10"/> </property>
<property class="UpgradeBlock">
<property name="ToBlock" value="steelLogSpike6"/>
<property name="Item" value="resourceForgedSteel"/>
<property name="ItemCount" value="10"/>
<property name="UpgradeHitCount" value="4"/>
</property>
<property name="DowngradeBlock" value="rScrapIronLogSpike5"/>
</block>
<block name="FireSteelLogSpike">
<property name="Extends" value="steelLogSpike6"/>
<property name="CreativeMode" value="Dev"/>
<property name="Damage" value="7"/>
<property name="Damage_received" value="10"/>
<property name="Texture" value="346,345,341,345,262,345"/>
<property name="ImposterExchange" value="imposterPyramid" param1="110"/>
<property name="DowngradeBlock" value="steelLogSpike6"/>
<property class="RepairItems"> <property name="ammoGasCan" value="25"/> </property>
</block>
</append>
</configs>
i add Condrete Spike And Fire Steel Spike