witchery using same ids as dartcraft 1.0.20 dw20 1.6.4

07:51:47 [SEVERE] Encountered an unexpected exception IllegalArgumentException
java.lang.IllegalArgumentException: Slot 1900 is already occupied by bluedart.block.BlockPowerOre@53c73e68 when adding com.emoniph.witchery.blocks.BlockGlowGlobe@4c2a33ec
        at net.minecraft.block.Block.<init>(Block.java:351)
        at com.emoniph.witchery.blocks.BlockGlowGlobe.<init>(BlockGlowGlobe.java:18)
        at com.emoniph.witchery.Witchery.init(Witchery.java:684)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at cpw.mods.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:545)
        at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
        at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
        at com.google.common.eventbus.EventBus.dispatch(EventBus.java:313)
        at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
        at com.google.common.eventbus.EventBus.post(EventBus.java:267)
        at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:201)
        at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:181)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
        at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
        at com.google.common.eventbus.EventBus.dispatch(EventBus.java:313)
        at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
        at com.google.common.eventbus.EventBus.post(EventBus.java:267)
        at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:112)
        at cpw.mods.fml.common.Loader.initializeMods(Loader.java:699)
        at cpw.mods.fml.server.FMLServerHandler.finishServerLoading(FMLServerHandler.java:107)
        at cpw.mods.fml.common.FMLCommonHandler.onServerStarted(FMLCommonHandler.java:355)
        at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:178)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:630)
        at net.minecraft.server.ThreadMinecraftServer.run(ThreadMinecraftServer.java:16)
07:51:47 [SEVERE] This crash report has been saved to: /minecraft/dw20/./crash-reports/crash-2014-04-15_07.51.47-server.txt