use LWP;
our $ua = LWP::UserAgent->new();
my $url = "http://www.google.com";
my $response = $ua->get($url);
my $request = $response->request();
print $request->as_string();

__END__
output
======
GET http://www.google.ca/
User-Agent: libwww-perl/5.64
[download]

Ouch, LWP has bugs.

The lack of HTTP/1.0 or HTTP/1.1 makes this an HTTP/0.9 request. That's fine, except that a HTTP/0.9 header consists of just the Request-Line, with no "header: value" pairs. The User-Agent line and the three CRLF after the first one are therefore invalid, but I doubt this is the problem.

An absolute-URI is specified in the Request-Line. That "is only allowed when the request is being made to a proxy". I'm not making the request to a proxy, so bug number two! You are making the request to a proxy, however, so that should be ok for you. *Should* be ok. I bet this is what it's chocking on nonetheless.