"501 (Not Implemented) Protocol scheme 'http' is not supported" Error

[rubis]

I want to write a perl code to save back HTML files of Web sites in order to analyse them. I first test by using the following code

$ua = LWP::UserAgent->new;
$req = HTTP::Request->new('GET',"

http://www.yahoo.com");

$res = $ua->request($req);

if ($res->is_error) {
print $res->as_string;
}

After I run it through CGI, I have got this error

"501 (Not Implemented) Protocol scheme 'http' is not supported"

Pls suggest me how to solve it..