if (itemstack != null && this.isOwner(par1EntityPlayer) && !this.worldObj.isRemote && itemstack.getItem() == Items.bone) {
            	if (!worldObj.isRemote) {
            		FMLNetworkHandler.openGui(par1EntityPlayer, Main.instance, GUIHandler.CAT_GUI, worldObj, 0, 0, 0);
            		System.out.println("ITWORKS");
            	}