My mc mod

Hello coders am mc am making a mc mod for minecraft and I have errors on it it's in my mod java and it's says basemod and private static final string modloader =null. It's errors for the item codeing that am having problems with and addOverride and addName is in erros. Am doing this from watching youtube video's if anyone know the codeing for these plz let me know and the item java is fixed of all it's errors. it's says the method addoveride string is unrefined for the type string says that for both of the addname and addoverride and the basemod says cannot be resolved for a type. here is my mod this is copyrighted by me so it's belongs to me thank you package net.minecraft.src;
import java.util.Random;

public class mc_firstmod extends BaseMod
{

public static final Item ethiumstone = new Itemethiumstone(500).setItemName("ethiumstone");
private static final String ModLoader = null;
private static final String ethuimstone = null;

public void load()
{

ethiumstone.iconIndex = ModLoader.addOverride("/gui/items.png" , "/items/ethiumstone.png");
ModLoader.addName(ethuimstone, "Ethiumstone");

}
public String getVersion()
{
return "3.14159265";
}
}