C#. CS1518. men vad är knas i min kod?

Tänkte att nån C#-kunnig kunde kolla på ett stycke kod och säga varför det blir fel (CS1518, Expected class, delegate, enum, interface, or struct). Jag har lagt in kommentarer ovanför de ställen där det blir knas... Som jag ser det borde det ju vara rätt...

using System;
using System.Collections.Generic;
using System.Text;

namespace Assignment2
{
class Menu
{
public void start ()
{
int choice = -1;

while (choice != 0)
{
WriteMenuText ();

choice = int.Parse(Console.ReadLine ()); //read user input

switch (choice)
{
case 1:
{
WriteMessageCodeNotImplemented ();
break;
}
case 2:
{
WriteMessageCodeNotImplemented ();
break;
}
case 3:
{
WriteMessageCodeNotImplemented ();
break;
}
case 4:
{
WriteMessageCodeNotImplemented ();
break;
}
default:
break;
}

}

Console.WriteLine ("\n");

}

}
//Här blir det tydligen något knas (CS1518)
public void WriteMenuText()
{
Console.WriteLine ("-----------------------------------------------------");
Console.WriteLine (" PROGRAM MENU");
Console.WriteLine ("-----------------------------------------------------");
Console.WriteLine (" Whole Numbers with For :1");
Console.WriteLine (" Floating Point Numbers with While :2");
Console.WriteLine (" Currency Converter with Do While-loop :3");
Console.WriteLine (" WasteSchedule :4");
Console.WriteLine (" Exit the program :0");
Console.WriteLine ("-----------------------------------------------------");
Console.Write ("Your choice: ");

}

//Här blir också knas (CS1518)
private void WriteMessageCodeNotImplemented (int choice)

{
string str = "Your choice is " + choice + " but the program is not complete yet.";
str += Environment.NewLine + "Please come again!";
Console.WriteLine (str);
}

}