JUDGEMENT!

src/main/java/com/hbm/blocks/generic/BlockBobble.java

@@ -217,6 +217,7 @@ public class BlockBobble extends BlockContainer implements IGUIProvider {
 	}
 
 	@Override
+	@SideOnly(Side.CLIENT)
 	public GuiScreen provideGUI(int ID, EntityPlayer player, World world, int x, int y, int z) {
 		return new GUIScreenBobble((TileEntityBobble) world.getTileEntity(x, y, z));
 	}

src/main/java/com/hbm/blocks/machine/BlockArmorTable.java

@@ -64,6 +64,7 @@ public class BlockArmorTable extends Block implements IGUIProvider {
 	}
 
 	@Override
+	@SideOnly(Side.CLIENT)
 	public GuiScreen provideGUI(int ID, EntityPlayer player, World world, int x, int y, int z) {
 		return new GUIArmorTable(player.inventory);
 	}

src/main/java/com/hbm/blocks/machine/NTMAnvil.java

@@ -176,6 +176,7 @@ public class NTMAnvil extends BlockFalling implements ITooltipProvider, IGUIProv
 	}
 
 	@Override
+	@SideOnly(Side.CLIENT)
 	public GuiScreen provideGUI(int ID, EntityPlayer player, World world, int x, int y, int z) {
 		return new GUIAnvil(player.inventory, ((NTMAnvil)world.getBlock(x, y, z)).tier);
 	}