Here we go:

java.lang.ClassCastException: mariculture.core.tile.TileOyster cannot be cast to mariculture.factory.tile.TileCustom
at mariculture.factory.blocks.BlockCustomHelper.getBlockHardness(BlockCustomHelper.java:54)
at mariculture.factory.blocks.BlockCustomBase.func_149712_f(BlockCustomBase.java:81)
at toast.specialAI.util.BlockHelper.shouldDamage(BlockHelper.java:26)
at toast.specialAI.ai.GriefSearch.tryTargetBlock(GriefSearch.java:128)
at toast.specialAI.ai.GriefSearch.checkCoords(GriefSearch.java:116)
at toast.specialAI.ai.GriefSearch.checkNext(GriefSearch.java:90)
at toast.specialAI.ai.GriefSearch.runSearch(GriefSearch.java:69)
at toast.specialAI.ai.SearchHandler.onServerTick(SearchHandler.java:66)
at cpw.mods.fml.common.eventhandler.ASMEventHandler_1150_SearchHandler_onServerTick_ServerTickEvent.invoke(.dynamic)
at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54)
at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:138)
at cpw.mods.fml.common.FMLCommonHandler.onPreServerTick(FMLCommonHandler.java:260)
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:536)
at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:111)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:427)
at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685)

Thank you for your time and effort.