problem when reading file

[shrimpy]

hi every one, i am new to python,
and coz i want to write a handy command for my linux machine, to find
a word in all the files which are under the current folder.

the code is half done, but when i run it, it complain, and i don`t know why???

can anyone help me have a look at it?


here is the message it complain
=======================================
file is : qt_plugins_3.3rc

Traceback (most recent call last):
  File "./python_script/svn_grep.py", line 34, in <module>
    searPatten(file,'are','no')
  File "./python_script/svn_grep.py", line 8, in searPatten
    openFile = open(file, 'r')
IOError: [Errno 2] No such file or directory: 'qt_plugins_3.3rc'


here are the code i wrote
---------------------------------------------------------------code begin
#!/usr/bin/python

import os
import string


def searPatten(file, patten, isCaseSensitive):
	openFile = open(file, 'r')
	lines = openFile.readlines()
	lineNum = 1
	for text in lines :
		words = text.split()
		existed = 0
		for word in words :
			if isCaseSensitive == 'yes' :
				if word.lower() == patten.lower():
					existed = 1
					break
			else:
				if word == patten :
					existed = 1
					break
		if existed == 1:
			print "line : " + str(lineNum) + " " + text
		lineNum += 1
	openFile.close()



for root, dirs, files in os.walk(os.getcwd()):
	for file in files:
		print "======================================="
		print "file is : " + file + "\n"
		searPatten(file,'are','no')

---------------------------------------------------------------code end