web access yields "503"

[roger_lynx]

Hi, I am porting a simple code from Perl, the website asks for 
usr/pwd and the server's side Perl script makes a temp ftp dir 
for a file upload.

The original Perl script connects okay, does its job. The same URL
stuffed into FF3 performs the same way.
My Python script I am sweating over for past four days (noob!) gets
consistently "503", even with user agent set to: 
Mozilla/5.0 (Windows;U; Windows NT 5.1; it; rv:1.8.1.11)Gecko/20071127 Firefox/2.0.0.11.

Snippets of relevant code below, heavily copied from this author:
http://www.voidspace.org.uk/python/articles/urllib2.shtml

Please, help me understand how this same code lets me log in into my
router usr/pwd running .asp, but this !@#$% perl script returns to me
w/503 c*ap?
Thank you.

Do I need to set any proxy? 
The server is on intranet and the FF3 is
set to proxy. 
The original Perl script did not use any proxy setting! 
LWP::

<pre>

url = http://bad_example.com/ftpsetup.pl?username=boofa&nodeid=42
#########################################################
# create a password manager
    password_mgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
# Add the username and password.
# If we knew the realm, we could use it instead of ``None``.
    password_mgr.add_password(None, url, uid, pcode)
    handler = urllib2.HTTPBasicAuthHandler(password_mgr)
    class Mopener(URLopener): version = "Mozilla/5.0 (Windows; U;
Windows NT 5.1; it; rv:1.8.1.11) Gecko/20071127 Firefox/2.0.0.11"

    opener = Mopener()

# create "opener" (OpenerDirector instance)

    opener = urllib2.build_opener(handler)
    opener.addheaders = [('User-agent', 'Mozilla/5.0 (Windows; U;
Windows NT 5.1; it; rv:1.8.1.11) Gecko/20071127 Firefox/2.0.0.11')]

    opener.version = "Mozilla/5.0 (Windows; U; 
Windows NT 5.1; it; rv:
1.8.1.11) Gecko/20071127 Firefox/2.0.0.11"

    print opener.version
# timeout in seconds
    timeout = 10
    socket.setdefaulttimeout(timeout)

# Install the opener all calls to urllib2.urlopen use our opener.
    urllib2.install_opener(opener)

    try:
        response = opener.open(url)
        # "http://www.useragent.org/" tested okay!!!
        print"ok = 1"
    except:
        print "error 1"
#####################################################################################

output from the above:

Mozilla/5.0 (Windows; U; Windows NT 5.1; it; rv:1.8.1.11) Gecko/
20071127 Firefox/2.0.0.11
error 1
Error code: 503
('Service Unavailable', 'The server cannot process the request due to
a high load')
</pre>