HTTP::Request::Form question

[Dong-Han Shin]

I've downloaded and installed HTTP::Request::Form module (version 0.7)  (also installed libwww-perl-5.48, URI-1.06, MIME-Base64-2.11,   HTML-Parser-3.07, libnet-1.0703, Digest-MD5-2.09,  HTTP::Request::Common,   HTML::TreeBuilder, LWP::UserAgent)   and tried to test the module with the example source in the man page.         #!/usr/local/bin/perl       use HTML::TreeBuilder;       use URI::URL;       use LWP::UserAgent;       use HTTP::Request;       use HTTP::Request::Common;       use HTTP::Request::Form;         my $ua = LWP::UserAgent->new;       my $url = url 'http://www.altavista.com/';       my $res = $ua->request(GET $url);       my $tb = HTML::TreeBuilder->new;       $tb->parse($res->content);       my @forms = @{$tb->extract_links(qw(FORM))};       my $f = HTTP::Request::Form->new($forms[0][1], $url);       $f->field("q", "perl");       my $response = $ua->request($f->press("search"));       print $response->content if ($response->is_success);   When I run the example code above, I encountered the problem as below.        Can't call method "traverse" on an undefined value      at /usr/local/lib/perl5/site_perl/5.6.0/HTTP/Request/Form.pm line 120.     Any help clearing this matter up would be greatly appreciated.