[Tutor] problem with mmap

[Ertl, John C CIV 63134]

All,
 
I am trying to work an example that I found at http://bitworking.org/news/132/REST-Tips-URI-space-is-infinite
 
When I try the code below I get an error and I am not able to figure it out. 
 
Thanks for any and all help.  I have two png and a text file (sortzip.txt) in the same dir as this code but I do not even get to that part...the mmap call is bad.  I have never used mmap before so this is new to me. I am running python 2.4 
 
John
############# code
from mmap import mmap
import os
from bisect import bisect_left
import sys
class Zipcodes(object):
    """Use mmap to treat the sorted file of zipcodes
    as an array"""
    def __init__(self):
        self.f = open("sortzips.txt", "r+")
        self.size = os.path.getsize("sortzips.txt")
        self.m = mmap(self.f.fileno(), self.size)
    def __getitem__(self, i):
        self.m.seek(6*i)
        return self.m.read(5)
    def __del__(self):
        self.m.close()
        self.f.close()
    def __len__(self):
        return self.size / 6
zipcodes = Zipcodes()
target = os.environ.get('PATH_INFO', '/')[1:]
found = ( zipcodes[bisect_left(zipcodes, target)] == target )
print "Status: " + ( found and "200 Ok" or "404 Not Found" )
print "Cache-control: max-age=172800"
print "Content-type: image/png"
print ""
file = open(found and "good.png" or "bad.png", "r")
png = file.read()
file.close()
sys.stdout.write(png)
##########################
error message when I try to run this.
 
Traceback (most recent call last):
  File "./zipcode.cgi", line 23, in ?
    zipcodes = Zipcodes()
  File "./zipcode.cgi", line 14, in __init__
    self.m = mmap(self.f.fileno(), self.size)
EnvironmentError: [Errno 22] Invalid argument
Exception exceptions.AttributeError: "'Zipcodes' object has no attribute 'm'" in <bound method Zipcodes.__del__ of <__main__.Zipcodes object at 0xbdf080cc>> ignored

###########################
 
John Ertl
Meteorologist
 
FNMOC
7 Grace Hopper Ave.
Monterey, CA 93943
(831) 656-5704
john.ertl at navy.mil
 
 
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