Build Errors

Question

I am getting a couple of build errors in my code.

The first of which is:
'wordFreq' is a 'variable' but is used like a 'method'

it says that on the line:
wordFreq(words[i].ToLower()) += 1;

I am also getting an error that says:
The name ' i ' does not exist in the current context


Here is my code:




using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Text.RegularExpressions;
using System.Collections;

namespace ConsoleApplication2
{
    class SplitTextFile
    {
        static void Main(string[] args)
        {
            FileStream file = new FileStream("input.txt", FileMode.OpenOrCreate, FileAccess.Read);
            StreamReader sr = new StreamReader(file);
            string s = sr.ReadToEnd();
            sr.Close();
            file.Close();
            char[] delim = { ' ', '\t', '\r', '\n' };
            string[] words = s.Split(delim);
            Hashtable wordFreq = new Hashtable();
            foreach (string word in words)
            {
                if (words[i] != "")
                {
                    bool realWord = true;
                    for (int j = 0; j < words[i].Length; j++)
                    {
                        if (char.IsLetter(words[i][j]) == false)
                        {
                            realWord = false;
                        }
                    }

                    if (realWord == true)
                    {
                        if (wordFreq.Contains(words[i].ToLower()))
                        {
                            wordFreq(words[i].ToLower()) += 1;
                        }
                        else
                        {
                            wordFreq.Add(words[i].ToLower(), 1);
                        }
                    }
                }
            }
            SortedList wordCount = new SortedList();

            foreach (DictionaryEntry de in wordFreq)
            {
                if (wordCount.ContainsKey(de.Value) == false)
                {
                    wordCount.Add(de.Value, de.Key);
                }
            }
        }
       
     }
}