Why my GuiHandler gives error [1.7.10][Unsolved]

[avaikulis]

on line

return new com.allans.Gui.inventory.GuiContainer(new com.allans.Gui.CustContainerWorkBench(new InventoryPlayer(player),world,x,y,z));

it shows an error in my gui handler i am trying to make guihandler show a gui that will open my customworkbench and for that i used original minecraft files can you please say to me how i can fix error :Cannot instantiate the type GuiContainer

 

Here my full guihandler

 

package com.allans.Gui;

import com.allans.Gui.inventory.GuiContainer;
import com.typesafe.config.Config;

import cpw.mods.fml.common.network.IGuiHandler;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.entity.player.InventoryPlayer;
import net.minecraft.tileentity.TileEntity;
import net.minecraft.world.World;

public class GuiHandler implements IGuiHandler
{

@Override
public Object getServerGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z) {
// TODO Auto-generated method stub
return null;
}

@Override
public Object getClientGuiElement(int ID, EntityPlayer player, World world, int x, int y, int z){
 if (ID == GuiContainer.GUI_ID){
	 return new com.allans.Gui.inventory.GuiContainer(new com.allans.Gui.CustContainerWorkBench(new InventoryPlayer(player),world,x,y,z));

         return null;
}
}


}
0

[Failender]

Show the error?

[Izzy Axel]

Don't return null on the server element, return a Container.