Buildcraft Block Conflict?

[PELogos]

First of all, apologies if this is in the wrong forum. I tried to find one where I'd be answered and where my content is relevant, but if I've chosen the wrong section I am sorry.

The server I run is currently not letting any users online because of the following error:

[iC2] Config loaded from (my server info)

2013-03-29 16:41:55 [sEVERE] java.lang.IllegalArgumentException: Slot 241 is already occupied by codechicken.enderstorage.BlockEnderChest@483ead69 when adding ic2.common.BlockRubSapling@aeaed8d

2013-03-29 16:41:55 [sEVERE] at net.minecraft.server.Block.<init>(Block.java:181)

2013-03-29 16:41:55 [sEVERE] at net.minecraft.server.BlockFlower.<init>(SourceFile:11)

2013-03-29 16:41:55 [sEVERE] at net.minecraft.server.BlockFlower.<init>(SourceFile:19)

2013-03-29 16:41:55 [sEVERE] at net.minecraft.server.BlockSapling.<init>(BlockSapling.java:18)

2013-03-29 16:41:55 [sEVERE] at ic2.common.BlockRubSapling.<init>(BlockRubSapling.java:14)

2013-03-29 16:41:55 [sEVERE] at net.minecraft.server.mod_IC2.load(mod_IC2.java:289)

2013-03-29 16:41:55 [sEVERE] at cpw.mods.fml.common.modloader.ModLoaderModContainer.init(ModLoaderModContainer.java:351)

2013-03-29 16:41:55 [sEVERE] at cpw.mods.fml.common.Loader.modInit(Loader.java:263)

2013-03-29 16:41:55 [sEVERE] at cpw.mods.fml.common.Loader.initializeMods(Loader.java:618)

2013-03-29 16:41:55 [sEVERE] at cpw.mods.fml.server.FMLBukkitHandler.onLoadComplete(FMLBukkitHandler.java:142)

2013-03-29 16:41:55 [sEVERE] at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:176)

2013-03-29 16:41:55 [sEVERE] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:438)

2013-03-29 16:41:55 [sEVERE] at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)

2013-03-29 16:41:55 [sEVERE] Unexpected exception

java.lang.IllegalArgumentException: Slot 241 is already occupied by codechicken.enderstorage.BlockEnderChest@483ead69 when adding ic2.common.BlockRubSapling@aeaed8d

at net.minecraft.server.Block.<init>(Block.java:181)

at net.minecraft.server.BlockFlower.<init>(SourceFile:11)

at net.minecraft.server.BlockFlower.<init>(SourceFile:19)

at net.minecraft.server.BlockSapling.<init>(BlockSapling.java:18)

at ic2.common.BlockRubSapling.<init>(BlockRubSapling.java:14)

at net.minecraft.server.mod_IC2.load(mod_IC2.java:289)

at cpw.mods.fml.common.modloader.ModLoaderModContainer.init(ModLoaderModContainer.java:351)

at cpw.mods.fml.common.Loader.modInit(Loader.java:263)

at cpw.mods.fml.common.Loader.initializeMods(Loader.java:618)

at cpw.mods.fml.server.FMLBukkitHandler.onLoadComplete(FMLBukkitHandler.java:142)

at net.minecraft.server.MinecraftServer.init(MinecraftServer.java:176)

at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:438)

at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)

Being a tekkit newbie--especially when it comes to server side aspects--I could use some help getting things up and running again. Any help would be appreciated, even if it's just pointing me to the right forum thread. Thanks!