Moderator nhinkle sent me an email message, but did not include a reply address. There is a "respond to" link at the bottom, but it's https://superuser.com/users/message/268#268, which comes up as a dead link.
What do I do?
The email was regarding having duplicate accounts, and it looks like you clicked the link for Daniel R. Hicks while logged in as DanH. That is why you can't access it - you can't read messages for a different account.
If you look in your global inbox, you should be able to see the moderator message. Click on that link, and you can respond there.
Alternatively, you can usually find contact info for the mods on their user profiles. If you check my user profile, you'll see an email address listed there. It's preferable to reply through the site's built-in message system, but you can always email us directly if need be. There is also the Ask a Moderator Chat Room.
Ninja edit: it looks like a Stack Exchange employee got your email response to firstname.lastname@example.org. Your accounts have now been merged.