cannot check secure links with W3C checklink

I am trying to use the W3C checklink to verify my site, running on the
command line. Some links on the site are secure, authenticated with a
username and password, to which I have access. I read on the check link
documentation page, that I needed to install LWP::Protocol::https which I
did.

I am supplying linkcheck with the -u -p -d options, but I get a 500
Internal Server Error for my secure links. The message is "You need".

I tried to simulate what checklink was doing in a standalone perl script:

require LWP::UserAgent; my $server = '<server>';
my $url = '<url>';
my $username = '<user>';
my $password = '<password>';
my $ua = LWP::UserAgent->new;
# $ua->ssl_opts(verify_hostname => 0); ### Uncomment this line and it works

my $request = HTTP::Request->new('HEAD', $url);
$request->authorization_basic($username, $password);

my $response = $ua->request($request); print $response->status_line;

When I uncomment the ssl_opts call, this works. When I comment it, I get
the 500 error.

I am running on Mac OS X 10.5.8, W3C::LinkChecker is up to date (4.81),
LWP::Protocol::https is up to date (6.03)

Should W3C checklink work for secure links when running on the command line?

Is there some other checklink configuration I need to perform?