Unexpected error

java.lang.NullPointerException: Unexpected error
	at net.minecraft.item.ItemStack.getDisplayName(ItemStack.java:538)
	at codechicken.microblock.BlockMicroMaterial.getLocalizedName(BlockMicroMaterial.scala:88)
	at codechicken.microblock.ItemMicroPart.getItemStackDisplayName(ItemMicroPart.scala:39)
	at net.minecraft.item.ItemStack.getDisplayName(ItemStack.java:538)
	at net.minecraftforge.client.GuiIngameForge.renderToolHightlight(GuiIngameForge.java:585)
	at net.minecraftforge.client.GuiIngameForge.renderGameOverlay(GuiIngameForge.java:157)
	at net.minecraft.client.renderer.EntityRenderer.updateCameraAndRender(EntityRenderer.java:1121)
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1022)
	at net.minecraft.client.Minecraft.run(Minecraft.java:910)
	at net.minecraft.client.main.Main.main(Main.java:112)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28)