Python web forms submission

I am trying to submit this web form and log in to this site: https://www.kalahari.net/profile/pipeline/signin.aspx

I keep getting the source code of the login site as output when the script is executed, so everything seems to work (no errors), but it just is not logged in. I cannot find what I am doing wrong. Please help. I am using Python 3.1.2, I cannot use Mechanize since the code must be written in Python 3.x

I think my problem might be the POST URL. I am sending login information, but I can’t understand what it is.

f=open("page_src.html",'wb') 
cj=cookiejar.CookieJar()

params=urllib.parse.urlencode({'ctl00$ctl00$cplhMain$cplhContent$txtEmail': 'username', 'ctl00$ctl00$cplhMain$cplhContent$txtPassword': 'pass'})

opener = req.build_opener(req.HTTPCookieProcessor(cj))
opener = urllib.request.FancyURLopener()
page = opener.open("https://www.kalahari.net/profile/pipeline/signin.aspx", params)

profilepage = opener.open("https://www.kalahari.net/profile/pipeline/profile.aspx")
source=profilepage.read()

f.write(source)
f.close()