package carpentersblocks.util;

import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.item.Item;
import carpentersblocks.util.registry.ItemRegistry;
import cpw.mods.fml.common.registry.LanguageRegistry;
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;

public class CarpentersBlocksTab extends CreativeTabs {

    public CarpentersBlocksTab(String label)
    {
        super(label);
    }

    @SideOnly(Side.CLIENT)
    @Override
    public Item getTabIconItem()
    {
        return ItemRegistry.itemCarpentersHammer;
    }

    @Override
    public String getTranslatedTabLabel()
    {
        return LanguageRegistry.instance().getStringLocalization("itemGroup.carpentersBlocks.name");
    }

}

package carpentersblocks.util;

import net.minecraft.client.resources.I18n;
import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.item.Item;
import carpentersblocks.util.registry.ItemRegistry;
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;

public class CarpentersBlocksTab extends CreativeTabs {

    public CarpentersBlocksTab(String label)
    {
        super(label);
    }

    @SideOnly(Side.CLIENT)
    @Override
    public Item getTabIconItem()
    {
        return ItemRegistry.itemCarpentersHammer;
    }

    @Override
    public String getTranslatedTabLabel()
    {
    	return I18n.format("itemGroup.carpentersBlocks.name", new Object[0]);
    }

}

Change tab translation to new I18n format.
Change tab translation to new I18n format.
