An integer is required? open()

Also of note is that starting with Python 2.6 the built-in function open() is now an alias for the io.open() function. It was even considered removing the built-in open() in Python 3 and requiring the usage of io.open, in order to avoid accidental namespace collisions resulting from things such as "from blah import *". In Python 2.6+ you can write (and can also consider this style to be good practice):

import io
filehandle = io.open(sys.argv[1], 'r')

Don't do import * from wherever without a good reason (and there aren't many).

Your code is picking up the os.open() function instead of the built-in open() function. If you really want to use os.open(), do import os then call os.open(....). Whichever open you want to call, read the documentation about what arguments it requires.

Because you did from os import *, you are (accidenally) using os.open, which indeed requires an integer flag instead of a textual "r" or "w". Take out that line and you'll get past that error.