Well your requested URL looks okay to me, but how do you know you aren't hitting a redirect, and it's some subsequent URL that's causing you grief?

A simple check to see whether this is the case would look something like (tested):

#! /usr/bin/perl -w

use strict;
use LWP::UserAgent;
use HTTP::Request;

my $ua = LWP::UserAgent->new;
my $res = $ua->simple_request( HTTP::Request->new('GET', shift ));

print $res->status_line, "\n";
[download]

If you get a 300, 301 or 302 you're being redirected, so you'll have to look farther afield. If, as it appears in your comments, you are using SOAP, why don't you take a look at the SOAP hierarchy on CPAN?