Python, Mechanize | Having issues with being logged out - python-2.7

Question

I'm learning python and running my first scraper using mechanize.
Goal: Login to a website, navigate to a list of URL's and return a chunk of text then write that to a CSV.
The code I'm using works great but as I run down the list I'm getting issues where after 10- 15 rows the entire html page is coming back rather than that chunk of text. Once the error happens it won't function correctly until I run the operation again but hits the snag after 10-15 again.
After looking looking at the html it looks as though I'm being logged out and can't figure out why. The URLs are all legit, if I test out getNum individually for all of the links it seems to work fine.
Last thing - The site needs Javascript and cookies to login
Here are what the functions look like
def get_Num(link): #takes in a URL, provided by the csv and finds the chunk of text I'm looking for
import urllib2
import cookielib
import urllib
import requests
import mechanize
# Browser
br = mechanize.Browser()
# Cookie Jar
cj = cookielib.LWPCookieJar()
br.set_cookiejar(cj)
# Browser options
br.set_handle_equiv(True)
br.set_handle_gzip(True)
br.set_handle_redirect(True)
br.set_handle_refresh(False)
br.set_handle_referer(True)
br.set_handle_robots(False)
# Follows refresh 0 but not hangs on refresh > 0
br.set_handle_refresh(mechanize._http.HTTPRefreshProcessor(), max_time=1)
# User-Agent (this is cheating, ok?)
br.addheaders = [('User-agent', 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.1) Gecko/2008071615 Fedora/3.0.1-1.fc9 Firefox/3.0.1')]
# The site we will navigate into, handling it's session
br.open('https://www.website.com/login')
#select the first form
br.select_form(nr=0)
#user credentials
br['session_key'] = login
br['session_password'] = pw
# Login
br.submit()
print 'logged in'
#open link
br.open(link)
html = br.response().read()
position1 = html.find('text')
position2 = html.find('>',position1)
targetNumber = html[position1:position2]
return targetNumber
def get_Info(inputFile,outputFile): # takes a CSV and runs getNum for ever url and then writes the whole thing to a csv
import urllib2
import re
import csv
with open(inputFile, "rb") as csvinput:
with open(outputFile, 'w+') as csvoutput:
reader = csv.reader(csvinput)
writer = csv.writer(csvoutput)
for rowNum, line in enumerate(reader):
vv = getNum(str(line[1]))
line.append(vv)