First, you did not actually explain what the problem is. Do you need a program that parses a string to check how many words of a certain length are there?

How much will you pay?

Code:
using System;
using System.Text.RegularExpressions;
using System.Text;
using System.Collections;

namespace ParserNamespace
{
	class Class1
	{
		public int[] ParseString(String text)
		{
			int [] vector = new int[6];
			Regex reg = new Regex(" |, | ,|,");

			StringBuilder sbuilder = new StringBuilder();

			foreach(string s in reg.Split(text))
			{
				if(s.Length<6) vector[s.Length-1]++;
				else vector[vector.Length-1]++;
			}

			return vector;
		}

		[STAThread]
		static void Main(string[] args)
		{
			Class1 test = new Class1();
			int [] results = test.ParseString("this is just a simple text,nothing more, nothing less");

			int i=1;
			foreach(int val in results)
			{
				Console.WriteLine("Words of length {0} : {1}",i++,val);
			}
		}
	}
}